Oh I 100% believe that the majority of D&D 5e players would be happier with a different game. For many different reasons. Some because they want more crunch, some because they want less. Some because they don't actually want to play a resource management dungeon crawl game at all. I mean, just look at how many players do one-fight-per-rest, and how many people cram social conflict into D&D despite the threadbare rules for it.

Unfortunately, D&D is such a big brand it just sucks all the air out of the room. Other games don't have the community or branding.

I mean, there's Pathfinder, but that's kind of the blues brothers "we've got both kinds of music: country and western" situation. It's very similar to D&D. I guess the next biggest is Vampire? And then way down at the end of the long tail there's like Fate, Gurps, shadowrun. I guess PbtA and Blades games are gaining some currency lately, too.