The network effects are part of the path dependency - they're what generate the cost of change (which is the standard cause of non-change in path-dependent explanation).There's also the aforementioned network effects, and people...well, for lack of a better term, staking part of their identity on the form of the game.
The bitter and acrimonious debates, particularly over what is permitted to count as "D&D," speak to a vein of identity that is bound up in being "a D&D player." In effect, for some, I think it flat doesn't matter whether the game tries to be more enjoyable, nor whether it tries to solve issues with its design. For these folks, the only thing that matters is having their identity validated, an identity built in some small way on a specific conception of D&D's essence and fundamental nature.
The identity issue I reckon is only a very small number of D&D players. Though they play an important role in popularising (or not) a particular version of D&D (see eg 4e) in virtue of their role in the networks, I don't think they are actually that numerous.