They have the next media rights renegotiation and (despite wishful thinking to the contrary) will likely command far more revenue than the Big 12 (as long as they keep USC, Oregon, Washington etc).
The real concern comes if, in the course of negotiations, ESPN/Fox/Amazon/whoever tells them they'd pay more if they brought Texas eyes with them.
At that point, they could decide to poach let's say four of Texas Tech, Oklahoma St, TCU, Baylor, Houston or BYU. Arizona schools, Utah, Colorado and the new 4 being the Eastern division.
Obviously if BYU is one of them, it's no big deal the we just enjoy being in the PAC16. But if they take Ok St, TCU, Baylor and Texas Tech, then we're joining a conference of West Virginia, Iowa St, Kansas and Kansas St. Which might be enough to get multiple teams reconsidering.
To clarify, I don't think it happens, but if it does fall apart, that's how it goes down. UCF and Houston already celebrated their AQ invite a decade ago after all.