$$ will likely be the determining factor. The SEC will want to know they have a good chance to get a 2nd-3rd team in at large. The PAC-12 want a guaranteed slot (as do all of the P-5). And even the ACC will have a different prospective the first time Clemson fails to win the ACC or has two losses - either case will likely result in the ACC being left out under current format. Absent agreement to expand, the P-5 might just consider to reallocate payouts to make the left out P-5 conference feel placated.