TV contracts are still mainly based on TV households, far less on eyes on the channels or games. The details aren't public, but the rumor when the SECNetwork started was that each subscriber in an SEC area paid $1.40 per month for the channel. TV subscribers in other areas paid much less, something like 25 cents. The SECNetwork gets more than $3 million per month from the Atlanta TV market alone. Currently the SEC is in two of the top 10 markets.(Atlanta and Houston) The Big10 is in 4.(New York, Chicago, Philadelphia, and Washington) After TX/OK and USC/UCLA each of them will pick up another top 10 market. (Dallas-SEC, LA-Big10) If the Big10 were to add Stanford, GT, and Rice they would have eight of the top 10 TV markets. Simply having those markets upped to an in-conference level could add $15-20 million per month to the conference revenue. (I don't have any real thoughts that they might go after Rice, I'm just looking at the money.)(LA is about double the other three markets)
Eyeballs on games will become important in the future. The PAC12 network never took off, so you probably don't see it out there, but a grandmother around Atlanta that only watches soap operas on weekday afternoons is still paying more than $1.40 for the SEC Network. Fox, ESPN, and the conferences are going to keep getting money from the majority of people who never watch college football for as long as they can. While they still can, having a team in the Atlanta market can provide $3-5 million per month even if not a single person in Atlanta watches that team.