The three conferences have zero control over this. It will literally boil down to OU and Texas breaking the contract and writing a check. It really boils down to when does that number hit a point both schools are comfortable with and they will be gone. You won't convince me that the Pac and B1G aren't having offline conversations with the Big 12 or the hateful 8.
The issue is not leaving the conference and the 75M (or whatever the exact exit fee is per school). Sure they can pay the fee and leave.... but the GOR means the league owns their TV rights until 2025. That is the reason they need the B12 dissolved. As long as the B12 exists, the B12 owns their TV rights until 2025.
Now, exactly what that means is more difficult to determine and would be fought over in court. All of the ACC schools and ND are looking at this because if tx/ou can get out early and what they need to pay, etc is going to be interesting to watch (clemson, fsu, unc, etc. can make a lot more money than what they are making in the ACC but their GOR is preventing them from leaving)..
But it is not just pay exit fee and leave. If they do, they can't get any tv money until 2025... or at least they will need to go to court in order to try to get their tv rights back before 2025... That is a much bigger deal than the $75M exit fee.
So...
That is why espn is trying to move teams out of the B12. Find homes for 4-6 more schools and those members can vote to dissolve the conference. Again, this is NOT ABOUT THE EXIT FEES... those can be solved. But if B12 exists the schools that leave, leave their TV rights behind until 2025 (same for ISU if they got an invite). This is why there is a chance that B12 lasts a little while longer.. Could be as long as 4 yrs. That means P5 status for another 4 yrs or so and then once tx/ou are gone, you have had 4 yrs to find a landing spot build your plan...
So, b10 wants to keep B12 together as long as they can... by forming an "alliance" with the pac, acc and all of them agreeing not to take any of the remaining teams, means the best option for the 8 is to stay in the B12 and keep it together until GOR expires.