If that were the case then the powers that be would be raiding the Big 12 instead of targeting Pac schools.
Normally yes, but the BIG 12 is the only conference that can end both the ACC and PAC 12. Essentially we survive and 2 die. Will the SEC and Big 10 then come at the B12? It depends.
If everyone is smart then no. Have the 60 remaining teams from the SEC, BIG 10 and Big 12 leave the NCAA in lockstep. Have our own FB playoff and BBall Tournament. Do some mild reshuffling to get geography aligned better and call it a day. 60 is more than enough schools to look more inclusionary which should reduce the chances of being charged with collusion. It would also keep the vast majority of Americans invested instead of just the Rust Belt and Southeast.
If the SEC and Big 10 get greedy then they will attack. If I were the Big 12 I'd make it so that the entire conference would have to vote "yes" to dissolve and that would lock down the GOR. Require the networks to review the financials every 5 years and adjust for market shifts with The SEC and B10 packages so that we don't get left behind financially. A decent corp lawyer could write this up so that there are no windows for escape. Simply do a 20 year contract with market adjustments every 5 years. Then the SEC/Big 10 would either have to leave the NCAA on their own or deal with the Big 12 on expanding the playoffs and frankly anything else they would want, which we would block just for ***** and giggles.
No one would look at a Big 10/ SEC basketball tournament as a National Championship. Ever.