And their lack of attempts to improve it; I mean, it's an open source project, there's a big "IMPROVE THIS DOC!" button on every documentation page.

Maybe it's because improving the doc has not too much benefit for the contributor because he/she already understands the badly documented problem. But improving code has instant benefit for the contributor because he probably fixing something he still using.

I think the simpler answer is that most people who complain about documentation cannot improve the docs because they don't know how. If they did understand what was being explained in the documentation, they wouldn't be complaining in the first place.

This is actually the same answer: when they finally learn enough to fix the documentation, there is no longer any personal benefit to doing so.

I was trying to make the distinction between those who get to the level of competence of contributing vs those who don't reach that point. The former group being people who don't complain about the docs (or at least not as loudly) while the latter group does. But I guess I didn't get that across clearly, sorry.

This is why my projects have always been willing to cut a deal with newbies to exchange stupid question credits for doc patches - i.e. "if you feel X is underdocumented, the core team will happily give you a personal tour of X provided you write up the results for the next guy to read" - which tends to help the incentive problem.

Yeah, I don't think the docs are bad, angular is just not a simple concept.