Imaro
Legend
I think D&D HAS evolved more than MOST games though. A lot has indeed stayed roughly the same, but over time the game has diffused and branched into various flavors, all within an overall genre. As you say, mostly niche games have simply come and gone and been replaced by more polished or different games, vs evolving in and of themselves. That's kind of what I was talking about. There's not a huge amount of point in evolving niche RPG #12 when you can just write niche RPG #13 and steal as much from #12 as you care to, within reason.
I always find it interesting when the argument that D&D hasn't evolved is made... I look at OD&D and IMO it's nothing like 5e in play or in much of it's design. Usually I find this argument to mean D&D hasn't evolved in the way I would like it to have done... or specific editions are used to create a "road" that supports this assertion are cited while those that don't are conveniently forgotten, and even then the argument doesn't seem to hold much water.