ESPN pays two thirds and Fox pays a third, of what is probably around a half billion dollar contract at this point. Most of the top football properties go to the mouse and Fox picked up weekly basketball.
And it was already turned to market. Without movement the B12 was closer to the $50-55m a year number, now they're closer to $30-35m. Their current contract is likely slightly undervalued due to 1) taking whatever you could in a terrible market. As the Pac showed, it was a bad time to ask for more and 2) as it reads in press releases, the B12 is getting a portion of the value returned in marketing. It cost them money, but it is a smart move in the long run. The SEC has the product on the field over the past decade, but 20 years ago they were helped greatly by CBS pumping tons of marketing into their brand on a weekly basis.
The next contract, in 2031, will be reflective of how well they do in this new structure.
There are two things at play here that may actually balance out each other. There is no doubt that Oklahoma and Texas have THE followings in the old Big 12, that's not really open for debate. So most other schools see a bump in viewership when they play them.
However, outside winning, one of the things that grows audiences the fastest is where you play. Texas and Oklahoma utterly dominated the T1 programming slots for the B12. When people tried to do spreadsheets pulling out these games you found you couldn't really compare what was left. If the B12 was on ABC or Fox, 80% of the time it was a team playing Texas or Oklahoma.
That's going to be a MAJOR change for the new B12. They have interest, for instance TCU/ISU drew over 4m this last year in a blow out, the CCG not featuring Texas nor Oklahoma was only 10% behind the B1G/SEC, but double the ACC/PAC. What ends up occuring when ESPN is not only featuring new teams on T1 outlets and marketing them more like the did the B1G when they had them is the wild card in all of this.
If the new B12 can get some post season success with multiple teams and put together really competitive games on T1 match ups, they'll get a boost in the next contract. If they don't, they won't.