I would have thought that if the rules were the issue the "house rule" fixes would be similar if not the same. But the comment I replied to suggested everyone was doing different things to the point where only some of the rules were the same.
Admittedly, I haven't done D&D5th. Too busy to do anything for a while, but even then, last I did were other RPGs.
Problem 1 is that D&D is the most popular and well known TTRPG, so people who are otherwise not curious about roleplaying games might still wind up playing D&D. They might not even realize there are other similar but different roleplaying games to even play!
Problem 2 follows from problem 1. Because D&D is seen as the 'default', many people try to make it be the one-size-fits-all game. It is actually really bad at this, because it has it's roots in a very specific type of tabletop wargame that is still visible in its DNA even today
So very often you find people who would probably prefer a more roleplaying focused game, playing D&D instead. And despite Wizards of the Coasts best efforts, D&D still plays better as a dungeon crawling wargame style game than a pure roleplaying game
My evidence of this is the insane popularity of Baldur's Gate 3, mostly because it had a lot of deep dialogue trees, not so much because it's a good tactical combat game (even though it is pretty good at that)
Admittedly, I haven't done D&D5th. Too busy to do anything for a while, but even then, last I did were other RPGs.