I have seen Increase badness based on distance between float and reference which was closed as a duplicate of our generic How to influence the position of float environments like figure and table in LaTeX?, but I'm still curious about if and/or how penalties might be used to assist the float placement algorithm.
It seems to me that a penalty could be inserted at each page break for each float in the deferred float "holding queue" to provide a greater incentive for the algorithm to place a float as the distance from the insertion point grows.
With the current "greedy" algorithm, this might not have much effect, since deferred floats are placed essentially as soon as they fit in the specified float position(s), but I think it might make a difference for full-width floats in two-column documents and it could also interact with any
\widowpenalty, and other penalties involving page-breaking locations.
\@floatpenaltyused for the float mechanism (in a quite involved way)
but doesn't have any more details, and this penalty is mentioned in neither David Carlisle's accepted answer to the penalty question nor Frank Mittelbach's accepted answer to How to influence the position of float environments like figure and table in LaTeX?