That Texas A&M and other are able to rally enough votes to prevent that and that Texas/Oklahoma have scorched the earth enough that the Big 12 is falling apart. They'd love to swoop in and make a play at that time.
For those focused on money, last year the PAC12 distributed an average of $33.6M to each school. The Big 12 distributed an average of $37.7M per school. For all intents and purposes, the conferences are currently financially equals. Adding Texas/Oklahoma to the PAC12 would vault them well above where the Big 12 currently is, especially since the PAC12 is the next to renegotiate their TV deals.