At this point, just restructure the whole thing like UK soccer. Have a five-tier system with annual promotion/relegation.
Each tier consists of two leagues, AFC/NFC style, that meet in the playoffs. The top tier consists of the current SEC+2 and some other league cobbled together from the other conferences. With Texas and OU moving to the SEC, there are pretty much only 10 teams outside of that conference that would draw a national audience, and even a couple of them are debatable.
Tier 2 is the same structure, with two 16-team leagues, as are tier 3-5.
The top 12 teams in each league at the end of the year would be safe from relegation, but the annual threat of relegation for the bottom four teams would make just about all the late season games must see TV. The bottom two teams in each league would automatically drop and be replaced by the top two teams from the level below.
Make it even more interesting by having the third and fourth worst teams in each league play the third and fourth best teams in the league below them in a bowl game that counts for sudden death promotion/relegation for those teams.
I would watch that. I'd probably watch all of it, including a late November game between directional Massachusetts and Li'l Sisters of the Poor if a promotion/relegation between tiers 4 & 5 were on the line.
SEC
1-16. Current Teams
E'rryone Else
1. Notre Dame
2. Clemson
3. Florida State
4. Penn State
5. Ohio State
6. Michigan
7. Oregon
8. USC
9. Wisconsin
10. BYU
11. Some Rando
12. Some Rando
13. Some Rando
14. Some Rando
15. Some Rando
16. Some Rando