USC and UCLA have been vocal about lack of revenue in the PAC12 vs other P5 conferences like B1G and the SEC. There were rumors USC exploring indy option vs. staying in the PAC-12.
Frankly, I just don't see media companies ponying up huge money to play teams like Oregon State and Washington State. USC and UCLA leaving together to B1G would definitely solve their revenue concerns although I can't imagine both being in the B1G without Cal and Stanford. If I am B1G, I go get USC, UCLA, Stanford, Washington, Colorado, and Oregon. The remaining PAC-12 6 teams can merge with 8x B12 leftovers while adding 2 more to form an almost P5 conference.
This all needs to happen before the next P12 and B1G media contract.