If they don’t care about ever getting any conference money, my guess is they would be admitted immediately if they agree to taking 0 conference pay for eternity. My guess is they eventually want a cut of the money, but are willing to wait for it.
The speculation that what changed Oregon and Washington’s minds was the promise that they will get a full share in the next tv deal makes a lot of sense to me. Joining the Big Ten makes sense if they get a full share eventually, probably no matter how long it takes.
This is probably the same calculus for SMU, only more so. They are willing to take nothing for as long as it takes, as long as they eventually get an equal share.
I don’t necessarily disagree with your larger point, but a lot of this was because the ACC pre-FSU joining (which is when Clemson won pre-Dabo) was hot garbage. I know beating out Maryland, NC State, and Duke for the most ACC championships is pretty exciting. Then a real football team joined in FSU and they rattled off 9 straight and 12/14 ACC championships.
The Big Ten may not have offered them a 5-6 year ramp up and instead offered no promises of ever getting a full share.
It sounds like ASU's president was able to convince the ABOR that the Pac 12 is still viable as long as Oregon/Washington stays and they are going to keep the two Arizona schools there unless Oregon/Washington leave.
If this is a 5-6 year thing, you obviously take it for the life-raft. If there is no guarantee of ever getting a full share, that's a much harder decision. Competing in a conference with every other team making 30 million more than you for a long period of time is rough.