https://www.yahoo.com/sports/pac-12-acc-had-chance-to-save-themselves-botched-playoff-142405174.html

Very interesting perspective on what went down during the CFP expansion talks. Apparently, the SEC, Big Ten, and ACC were in favor of expanding to 12 teams when the current deal expires. The Pac12 even went as far as saying that it supported CFP expansion. The Pac12 then voted against playoff expansion anyway, along with the Big12.

All this could explain why USC and UCLA decided to contact the Big Ten about applying for membership and why the Big Ten ultimately decided to, as some put it, stab the Pac12 in the back and pretty much blow up the alliance.

Also, it is reported that the remaining 10 teams in the Pac12 have reportedly contacted other conferences about membership (Big Ten, Big12). It will be interesting to see how things transpire.