players for a long, long time.
The ease of transfer restrictions could well play into this - but I think we still see talented players at the end of the P4 bench move to lower-level teams for playing time and the NIL money available for the best players even on smaller-market teams.
The traditional Cinderella team makes a run because some nobody goes on a streak, despite the mismatch in talent. We still had that this year - see McNeese State, Drake, and close calls by UCSD, Robert Morris, and High Point.
The MWC, WCC, and Big East had some stellar Round 1 performances and each barely missed the Sweet 16. They're not going away.
IMO, the bigger factor is realignment. The SEC added two major programs from the Big 12; the Big 12 'backfilled' with top-level quality from the PAC 12 and AAC plus BYU; the Big Ten and ACC also added quality and depth from the PAC 12 and AAC. Realignment has caused consternation in conference strength of schedule and the committee's seeding. I think we see the PAC 12 resurge once we see Gonzaga and SDSU in the same league with the best of the MWC and WCC.
And, BYU's rise in all of this is owing not only to realignment, but also to NIL and rule changes. We always play by the rules...and the rules have adjusted to enable us to legitimately compete with the cream of the crop.