I think 3e could have forked to either 4e or 5e, but I also think that both a 4e-like and a 5e-like system had to happen. I think 6e will be mostly 5e-like, but I'm really hoping that they'll make more 4e style monsters. (Truthfully, though, I expect the overriding aspects of 6e will be how online-connected it is, not changes to the system.) I don't think 4e makes a great version of D&D, but I do think some aspects should be incorporated into D&D (monster design, primarily).
4e is exactly what I'd expect to happen when you take a single character skirmish combat game and try to turn it into a TTRPG with no real alterations on what the character abilities were. Honestly, I'd like to see a 4e style game still continue to exist alongside D&D. It's a great game for people who want high depth tactical combat, and it's one that I think would benefit from a real revision and cleanup (not to mention better online resources). I think essentials was the wrong direction, as it felt like it was trying to bring back people who didn't like the new system and just turned off the people who did like it.
Maybe that system is PF2 -- I don't know, I loaned by PF2 book to a friend in March 2020 and I haven't seen him since then, although my first take was that the game spent 5-6 levels too many getting you to what felt like a minimum viable character -- but there's a lot to like about 4e as a game, just not with the D&D branding. It's like an M. Night Shayamalan movie. The movies are fairy tales with happy endings, but some idiot keeps marketing them as horror thrillers. The movies aren't bad (well, some of them certainly are) they're just drawing in the wrong audiences expecting the wrong movie.