The Big12 has their TV deal in place, an auto-bid to the NCAA basketball tournament, and they will almost certainly be one of the top six conference champions for the new CFP format, so there's lots to lose and nothing to gain if they just skip off to another conference.
Baylor, Kansas, Iowa State, TCU, and the rest of the leftovers will invite BYU, Houston, UCF and a few others in order to hold the Big12 together and keep their seat at the big boys table.