I think the only real change that you could call "evolution" has been submission defense for the more basic and well-known submissions like arm triangles/armbars/triangles/guillotines. Those still end fights occasionally but not like they used to. Also "dominant" positions on the ground are less dominant than before (full mount used to damn near be a guaranteed fight-ender), and less fighters throw strikes on the ground now in fear of scramble opportunities, but I don't think that's necessarily evolution, just change. I do think the floor has raised a bit on striking technique as well, the average fighter of 2026 has better striking than the average fighter of 2005, but the ceiling is the same.
My point is, the elites are comparable throughout the 2000's, 2010's, and 2020's. Elite is elite. I don't think the ceiling has changed whatsoever. I don't know if floor-raising is necessarily evolution.
I agree there, and that's kind of the goal of a lot of MMA gyms, at least in America, which has kept fighters a bit stagnant technically.