The media rights deal is already locked in. New revenue to add additional teams would have to come from a new media source other than Fox - CBS or NBC
Those three networks already own the prime time slots for big ten football
Fox - noon
CBS - 3:30
NBC - evening
So the 3 most attractive big ten matchups are already off the table . Any new media partner would be bidding on at best the 4th best game to be aired in unfavorable time slot. Given that I doubt a new media bid that increases team revenues will materialize