It is interesting because Fox pushed for the P12 schools to be added, but they were the ones affected the most by it. Contractually, they aren't allowed to broadcast a 9:00 a.m. local start time. So anytime OSU/UM/PSU/Nebraska goes out west, it's automatically going on NBC/CBS(unless it's an 11:00 p.m. ET start like UCLA/Oregon was). This all that added inventory will only go to CBS/NBC. UCLA and Washington being down this season also haven't helped, but banking on UCLA isn't a great strategy.
According to everything I've read, Fox gets the first 3 selections. Apparently they picked week 14(OSU/UM), week 2(Texas/UM), and then traded the 3rd selection to NBC, which was this past week of Oregon/OSU, but that made sense since they couldn't select it anyway. PSU/OSU and UM/OSU are going to do huge numbers, but I would agree, they now have gotten the short end of it. It also hurts that when SC came East to play UM, that was a CBS selection. So Fox got stuck with Marshall/OSU. It could be worse as OSU is obviously a huge draw, but not what SC/UM is going to pull.
Through 7 weeks this is the avg viewing audience:
Fox Big Noon - 4.27 million
NBC - 4.08 million
CBS - 3.82 million
But if memory serves, I think Fox is paying an extra $200 million per year in the deal to have these first couple selections. Certainly isn't worth an extra $200 million for an additional 200K viewers IMO.