I think a lot of people are misinterpreting all the "we're staying together, we're committed to the PAC" talk as meaning no one wants to leave, they all hate the idea of associating with the Big XII, etc.
Fact is, Arizona and ASU have been unhappy in that conference for years. UCLA's athletics budget has such a gigantic hole in it that they were going to have to drop a bunch of sports if they stayed. You'd assume others in the conference have similar financial issues.
Colorado has made far less money as a PAC member than they would've had they stayed in the Big XII. Their football program is a shell of its former self, and their facilities are now way behind other P-5 schools.
The Buffs football team looks very WAC like. It was really noticeable in the game I watched last year when they played TCU. The speed, size, strength, athleticism difference was hugely in TCU's favor
PAC teams staying in that conference risk becoming so far behind other P-5 teams that they'll never catch up.
So really you have to think all this chummy comaraderie is just a show so a media deal can somehow get cobbled together. This way teams leaving can do so with a clear conscience that they didn't blow things up, and did everything they could to keep things together until the very end.