A motivator for USC, UCLA (and to lesser extent BYU) getting into the new conferences was fewer late games. So I imagine those teams/fanbases won't be happy to have every home game starting late.

UCLA has been a pretty terrible ratings draw (compared to their slot) and USC might have enough juice to not play EVERY home game super late. BYU seems largely resigned to that fate, though I'd bet they'll also push for a few home games during daylight hours.

But that gives (at most) 1 per week for FOX and one every other week for whoever ends up with the Big 12 contract. There's still value to be had there - though you're correct that taking Oregon, Washington and Stanford (for example) would likely give enough inventory to regularly fill those without upsetting any team by forcing them to always play late at home.