How to convert tabular to longtable? Typical suggestions don't work

Question

I've seen similar questions, and answers typically say I only need to do three things: (i) remove begin and end table, (ii) replace begin and end tabular with begin and end longtable, (iii) load the longtable package.

When I apply these 3 steps to the code below, it still does not work? Is there any other adjustment I need to make?

%%% 01. LOADING PACKAGES
\documentclass[a4paper, 8pt]{article}
\usepackage{geometry}
\usepackage{array}
\usepackage{fancyhdr}
\usepackage{amsmath, amsthm, amssymb}
\usepackage{graphicx}
\usepackage{hyperref}
\usepackage{indentfirst}
\usepackage{pdflscape}
\usepackage{rotating}
\usepackage[utf8]{inputenc}
\usepackage{enumitem}
%\usepackage{euler}
\usepackage{bm}
\usepackage{econometrics}
\usepackage{booktabs}
\usepackage{amsfonts, empheq, mathrsfs}
\usepackage[dvipsnames]{xcolor}
\usepackage{extsizes}

%%% 02. CUSTOMISING FORMAT
\renewcommand{\baselinestretch}{1.3}
\setlength{\parskip}{1em}
\setlength{\skip\footins}{2cm}
\setlength{\footnotesep}{0.5cm}

%%% 03. POPULATING TEXT FIELDS
\title{S140 Behavioural Economics}
\author{}
\date{}

%%% 04. PRODUCING PERSONALIZED COMMANDS
\newcommand{\xb}[1]{\pmb{#1}}
\newcommand{\xbh}[1]{\pmb{\hat{#1}}}
\newcommand{\xbi}[1]{\pmb{{#1}^{-1}}}
\newcommand{\xbt}[1]{\pmb{{#1}^{'}}}
\newcommand{\tabitem}{~~\llap{\textbullet}~~}
\newcommand{\fconcepts}[1]{\textcolor{blue}{#1}}
\newcommand{\fquestions}[1]{\textcolor{red}{#1}}

%%% 05. TYPESETTING DOCUMENT
\begin{document}

        \newgeometry{top=0.5cm, bottom=0.5cm, left=0.5cm, right=0.5cm, asymmetric}
        \begin{landscape}
        
        \begin{table}[h!]
            \section{Overview of papers}
            
            \resizebox{\columnwidth}{!}{
                \begin{tabular}{|m{3.5cm}|m{9cm}|m{9cm}|m{17cm}|m{7cm}|}
                    \hline
                    \textbf{Paper}&\textbf{Objective}&\textbf{Methodology}&\textbf{Findings}&\textbf{Caveats}\\
                    \hline
                    
                    
                    \textbf{01. Roth et al. (1991):}
                    
                    Bargaining and Market Behavior, An Experimental Study
                    %OBJECTIVE
                    & 
                    \begin{itemize}
                        \item The three main goals were (i) to compare behaviour in related bargaining and market environments, (ii) to compare behavior in very different subject pools, and (iii) to use such differences to study out-of-equilibrium behaviour. 
                        \item Another important methodological goal was to learn how to deal with experimental design problems associated with multinational experiments, such that factors like language or currency could be controlled for, and cultural differences can be analyzed.
                    \end{itemize}
                    %METHODOLOGY
                    &
                    \begin{itemize}
                        \item Bargaining: Ultimatum game, two players, one makes a proposed division of the sum, the other can accept (and earn the proposed share) or reject (and both get zero). Ten sessions.
                        \item Market: Buyers submit offer to single seller, for object worth same amount to every buyer, and nothing to seller. Seller can either accept the highest price offered (receiving that amount, with buyer receiving the object’s value minus that amount, and others receiving zero) or reject it (all get zero). Ten markets.
                        \item Authors controlled for experimenter (ran experiences in Pittsburgh), language (translator national of relevant country), and currency (tokens as currency) effects.
                    \end{itemize}
                    %FINDINGS
                    &
                    \begin{enumerate}
                        \item Theoretical equilibrium: one player receives all the wealth (in the bargaining, the player who proposes the division; in the market, the seller).
                        \item Market environment: the observed market outcomes converge quickly to the perfect equilibrium, and do not deviate once reached, with no payoff-relevant differences observed between countries.
                        \item Bargaining environment: the observed bargaining outcomes are significantly different from the equilibrium predictions, with substantial differences between countries.
                        \item Offer and probability of acceptance: within every country these two variables were inversely related (low offers rejected more frequently than high offers), but the same does not hold across countries (higher disagreement not observed in countries with lower offers).
                        \item Role of experience in between-country differences: as subjects gained experience, between-country differences in market outcomes became smaller, while in bargaining outcomes they grew larger. This supports the view that differences in bargaining behaviour are not due to differences in languages, currencies, or experimenters, but other causes. 
                        \item Role of culture: culture is offered as a source of observed subject-pool differences, and authors suggest laboratory experimentation as a path for future research.
                    \end{enumerate}
                    
                    \fconcepts{\underline{Key concepts:}
                    \begin{itemize}
                        \item -
                    \end{itemize}}
                    %CAVEATS
                    &
                    \begin{enumerate}
                        \item Much higher percentage of army veterans in Israel and Yugoslavia than US or Japan.
                        \item Subjects were economics/business/psychology students, so sample is arguably contaminated.
                        \item Relatively small sample sizes.
                    \end{enumerate}
                
                    \fquestions{\underline{Questions:}
                    \begin{itemize}
                    \item What are the implications of changing the experiment from $10 to $30? Why would this change how subjects behave?
                    \end{itemize}}
                    \\
                    
                \hline
                    
            \end{tabular}
            }
        \end{table}
        \end{landscape}
                     
    
        
\end{document}

Answer 1

In addition to changing the nested table/tabular environments to a single longtable environment, you must also -- as already pointed out by @DavidCarlisle -- get rid of the \resisebox wrapper in order to (a) page breaks to occur if and when needed and (b) avoid typesetting the material at a microscopic font size. Remember: The basic document font size is 8pt -- you really don't want to go much smaller than that, unless you simply despise your readers and wish to make their enjoyment of your paper worse than zero...

Next, do replace the outlandishly large column widths -- 17cm, really?! -- with more sensible choices. In addition, since your code loads the enumitem package anyway, you might as well make use of that package's \newlist and \setlist directives to create variants of the enumerate and itemize environments that are much more compact than the default ones. (See the code below for some specific suggestions.) Finally, do consider giving the table a much open "look" by getting rid of all vertical lines and using the macros of the booktabs package instead of \hline.

\documentclass[a4paper, 8pt]{extarticle}
\usepackage{geometry}
\usepackage{array}
\usepackage{fancyhdr}
\usepackage{amsmath, amsthm, amssymb}
%%\usepackage{graphicx} % 'rotating' loads 'graphicx' automatically
\usepackage{indentfirst}
\usepackage{pdflscape}
\usepackage{rotating}
\usepackage[utf8]{inputenc}
\usepackage{enumitem}
%\usepackage{euler}
\usepackage{bm}
\usepackage{econometrics}
\usepackage{booktabs}
\usepackage{%%amsfonts, % 'amssymb' loads 'amsfonts' automatically
    empheq, mathrsfs}
\usepackage[dvipsnames]{xcolor}
%%\usepackage{extsizes} % load 'extarticle' document class instead
\usepackage{hyperref}


%%% 02. CUSTOMISE FORMAT
%%\renewcommand{\baselinestretch}{1.3} % don't manipulate '\baselinestretch' directly
\usepackage[nodisplayskipstretch]{setspace}
\setstretch{1.3}

\setlength{\parskip}{1em}
\setlength{\skip\footins}{1cm}
\setlength{\footnotesep}{0.5cm}

%%% 03. POPULATE TEXT FIELDS
\title{S140 Behavioural Economics}
\author{}
\date{}

%%% 04. PRODUCE PERSONALIZED COMMANDS
\newcommand{\xb}[1]{\pmb{#1}}
\newcommand{\xbh}[1]{\pmb{\hat{#1}}}
\newcommand{\xbi}[1]{\pmb{{#1}^{-1}}}
\newcommand{\xbt}[1]{\pmb{{#1}^{'}}}
\newcommand{\tabitem}{~~\llap{\textbullet}~~}
\newcommand{\fconcepts}[1]{\textcolor{blue}{#1}}
\newcommand{\fquestions}[1]{\textcolor{red}{#1}}

%%% new code
\usepackage[normalem]{ulem} % for \uline macro
\usepackage{longtable,ragged2e}
\newlist{myitemize}{itemize}{1}
\setlist[myitemize,1]{label=\textbullet, leftmargin=*, nosep,
          before={\begin{minipage}[t]{\hsize}},
          after={\end{minipage}}}
\newlist{myenumerate}{enumerate}{1}
\setlist[myenumerate,1]{label=\arabic*., leftmargin=*, nosep,
          before={\begin{minipage}[t]{\hsize}},
          after={\end{minipage}}}
\newcolumntype{P}[1]{>{\RaggedRight}p{#1}}

%%% 05. TYPESET DOCUMENT

\begin{document}

\newgeometry{margin=5mm, asymmetric}

\begin{landscape}
\section{Overview of papers}

\begingroup
\setstretch{1.0} % revert to single-spacing 
\begin{longtable}{P{3cm}P{5cm}P{5cm}P{8cm}P{5cm}}

\toprule
\textbf{Paper}&\textbf{Objective}&\textbf{Methodology}&\textbf{Findings}&\textbf{Caveats}\\
\midrule
\endhead

\midrule
\multicolumn{5}{r@{}}{\small\em continued on following page}
\endfoot

\bottomrule
\endlastfoot

%% Body of table
                    
01.\ Roth et al.\ (1991)
                    
Bargaining and Market Behavior, An Experimental Study &

%OBJECTIVE
\begin{myitemize}
\item The three main goals were (i) to compare behaviour in related bargaining and market environments, (ii) to compare behavior in very different subject pools, and (iii)~to use such differences to study out-of-equilibrium behaviour. 
\item Another important methodological goal was to learn how to deal with experimental design problems associated with multinational experiments, such that factors like language or currency could be controlled for, and cultural differences can be analyzed.
\end{myitemize} &

%METHODOLOGY
\begin{myitemize}
\item Bargaining: Ultimatum game, two players, one makes a proposed division of the sum, the other can accept (and earn the proposed share) or reject (and both get zero). 

Ten sessions.
\item Market: Buyers submit offer to single seller, for object worth same amount to every buyer, and nothing to seller. Seller can either accept the highest price offered (receiving that amount, with buyer receiving the object's value minus that amount, and others receiving zero) or reject it (all get zero). 

Ten markets.
\item Authors controlled for experimenter (ran experiences in Pittsburgh), language (translator national of relevant country), and currency (tokens as currency) effects.
\end{myitemize} &

%FINDINGS
\begin{myenumerate}
\item Theoretical equilibrium: one player receives all the wealth (in the bargaining, the player who proposes the division; in the market, the seller).
\item Market environment: the observed market outcomes converge quickly to the perfect equilibrium, and do not deviate once reached, with no payoff-relevant differences observed between countries.
\item Bargaining environment: the observed bargaining outcomes are significantly different from the equilibrium predictions, with substantial differences between countries.
\item Offer and probability of acceptance: within every country these two variables were inversely related (low offers rejected more frequently than high offers), but the same does not hold across countries (higher disagreement not observed in countries with lower offers).
\item Role of experience in between-country differences: as subjects gained experience, between-country differences in market outcomes became smaller, while in bargaining outcomes they grew larger. This supports the view that differences in bargaining behaviour are not due to differences in languages, currencies, or experimenters, but other causes. 
\item Role of culture: culture is offered as a source of observed subject-pool differences, and authors suggest laboratory experimentation as a path for future research.
\end{myenumerate}
                    
\bigskip
\fconcepts{\uline{Key concepts}}
\begin{myitemize} \color{blue}
\item --
\end{myitemize}  &

%CAVEATS
\begin{myenumerate}
\item Much higher percentage of army veterans in Israel and Yugoslavia than US or Japan.
\item Subjects were economics\slash business\slash psychology students, so sample is arguably contaminated.
\item Relatively small sample sizes.
\end{myenumerate}
                
\bigskip
\fquestions{\uline{Questions}}
\begin{myitemize} \color{red}
\item What are the implications of changing the experiment from $10$ to $30$? Why would this change how subjects behave?
\end{myitemize}
\\
                    
\end{longtable}
\endgroup


\end{landscape}     
        
\end{document}

Answer 2

A supplement to nice @Mico answer (+1). With use of tabularray package amd litle bit diiferent deginition commands \fconcepts and \fquestions.

In preamble are considered only stuff related to table.

\documentclass[a4paper, 8pt]{extarticle}
\usepackage{geometry}
\usepackage{pdflscape}
\usepackage[nodisplayskipstretch]{setspace}
\setstretch{1.3}

\usepackage{bm}
\usepackage{microtype}  % new

\usepackage{enumitem}
\newlist{tabitem}{itemize}{1}
\setlist[tabitem,1]{nosep,
                    parsep=0.5ex, % added
                    label=\textbullet, 
                    leftmargin=*,
                    before=\begin{minipage}[t]{\linewidth},
                    after =\end{minipage}
                    }
\newlist{tabenum}{enumerate}{1}
\setlist[tabenum,1]{nosep,
                    parsep=0.5ex, % added
                    label=\arabic*., 
                    leftmargin=*, 
                    before=\begin{minipage}[t]{\hsize},
                    after =\end{minipage}
                    }
\usepackage{econometrics}
\usepackage[normalem]{ulem} % for \uline macro
\newcommand{\fconcepts}[2]{\color{blue}{#1}\par #2} % changed
\newcommand{\fquestions}[2]{\color{red}{#1}\par #2} % changed

\usepackage[dvipsnames]{xcolor}
\usepackage{tabularray}
\UseTblrLibrary{booktabs, varwidth}

\begin{document}
\newgeometry{margin=5mm, asymmetric}
\begin{landscape}
\setstretch{1.0} % revert to single-spacing
    \begin{longtblr}[
caption = {Overview of papers},
  label = {tab:papers}
                    ]{colspec = {@{} X[0.6,j] X[j] X[j] X[1.6,j]  X [j] },
                       row{1} = {font=\bfseries, c},
                      measure = vbox,
                     }
    \toprule
Paper
    &   Objective
        &   Methodology
            &   Findings
                &   Caveats             \\
    \midrule
%% Body of table
01.\ Roth et al.\ (1991)

Bargaining and Market Behavior, An Experimental Study
    &   %OBJECTIVE
        \begin{tabitem}
    \item   The three main goals were (i) to compare behaviour in related bargaining and market environments, (ii) to compare behavior in very different subject pools, and (iii)~to use such differences to study out-of-equilibrium behaviour.
    \item   Another important methodological goal was to learn how to deal with experimental design problems associated with multinational experiments, such that factors like language or currency could be controlled for, and cultural differences can be analyzed.
        \end{tabitem}
        &   %METHODOLOGY
            \begin{tabitem}
        \item Bargaining: Ultimatum game, two players, one makes a proposed division of the sum, the other can accept (and earn the proposed share) or reject (and both get zero).

            \emph{Ten sessions.}
        \item Market: Buyers submit offer to single seller, for object worth same amount to every buyer, and nothing to seller. Seller can either accept the highest price offered (receiving that amount, with buyer receiving the object's value minus that amount, and others receiving zero) or reject it (all get zero).

            \emph{Ten markets.}
        \item Authors controlled for experimenter (ran experiences in Pittsburgh), language (translator national of relevant country), and currency (tokens as currency) effects.
            \end{tabitem}
            &   %FINDINGS
                \begin{tabenum}
            \item Theoretical equilibrium: one player receives all the wealth (in the bargaining, the player who proposes the division; in the market, the seller).
            \item Market environment: the observed market outcomes converge quickly to the perfect equilibrium, and do not deviate once reached, with no payoff-relevant differences observed between countries.
            \item Bargaining environment: the observed bargaining outcomes are significantly different from the equilibrium predictions, with substantial differences between countries.
            \item Offer and probability of acceptance: within every country these two variables were inversely related (low offers rejected more frequently than high offers), but the same does not hold across countries (higher disagreement not observed in countries with lower offers).
            \item Role of experience in between-country differences: as subjects gained experience, between-country differences in market outcomes became smaller, while in bargaining outcomes they grew larger. This supports the view that differences in bargaining behaviour are not due to differences in languages, currencies, or experimenters, but other causes.
            \item Role of culture: culture is offered as a source of observed subject-pool differences, and authors suggest laboratory experimentation as a path for future research.
                \end{tabenum}
            \bigskip
            \fconcepts{\uline{Key concepts}}%
                      {
                \begin{tabitem} 
            \item --
                \end{tabitem}
                      }
                &   %CAVEATS
                    \begin{tabenum}
                \item Much higher percentage of army veterans in Israel and Yugoslavia than US or Japan.
                \item Subjects were economics\slash business\slash psychology students, so sample is arguably contaminated.
                \item Relatively small sample sizes.
                    \end{tabenum}
            \bigskip
            \fquestions{\uline{Questions}}
                       { 
                \begin{tabitem} 
            \item What are the implications of changing the experiment from $10$ to $30$? Why would this change how subjects behave?
                \end{tabitem}
                        }   \\
    \midrule
    \end{longtblr}
\end{landscape}
\restoregeometry
\end{document}