I'd like to answer this question as someone who only started using ConTeXt last year and had similar concerns going in. The following is more of a user perspective rather than an evaluation of commercial potential.
As many people have pointed out, the documentation is in many cases
over a decade old...
It's true that some (much?) of the documentation on the ConTeXt wiki is patchy or a bit out of date. However, I have found many of the published manuals to be largely exceptional.
- The reference manual is excellent (looks like updated in 2013)
- Although not ConTeXt per se, the Metafun manual has been a revelation for me
- The publications and units manuals are good examples of relatively recent package-specific documentation
On top of the core manuals, there are a number of tutorial-style publications that I found extremely useful:
As Henri Menke pointed out in the comments, there are quite a few other good manuals that I originally missed: ConTeXt MKIV: An excursion, Fonts out of ConTeXt, ConTeXt Lua documents, Still going on, On and on, and the Commands reference.
Overall, I found the much more standardized nature of ConTeXt to make up for the lower volume of documentation. Getting familiar with how some environments work enabled me to make guesses about others -- something I never learned to do in LaTeX.
While there seems to be a constant froth of LaTeX development activity...
From what I gather, much of the development activity in LaTeX is related to packages rather than the LaTeX core. As discussed to some extent in this question, ConTeXt requires far fewer packages to get things done, and much of the core functionality is built in. I see the reduced volume of competing packages as a positive rather than a negative.
That said, as Aditya pointed out in the comments, the context beta is under ongoing development. And Hans Hagen recently asked about feature requests for a new version.
While there seems to be a constant froth of [...] support in these forums, the ConTeXt world is relatively
If you are talking about StackExchange, I'd guess that at least half of the questions I see about TeX/LaTeX are "draw this for me in Tikz", so I'm not sure that the volume of questions should be compared directly. That said, practically every single question I have asked here or on the mailing list has been answered within basically 24 hours. There are a number of very knowledgeable members here and the mailing list offers access to more, including the developers of ConTeXt, who are very actively involved.
The state of the community probably has more to do with your needs than anything else. Is there anything specific that you are looking for that you haven't been able to find?