That may be correct, Omni. From another perspective, though, you don't have a valid contract where one party simply agrees to do what they are already legally obligated to do.

In this case, though, if I understand your post correctly:

The Big XII has to allow (not air - the networks air the games) the games to be aired that the networks want aired and then pay the schools accordingly.

Since the Big XII has accepted this duty, there is perhaps a valid contract in this because the Big XII wasn't legally obligated to do this prior to signing and so this forms the consideration necessary to have a valid contract.

Also, the Big XII choosing NOT to exercise a right they have (in this case, possibly choosing which games are aired on TV) by offering it as consideration for the GOR could be seen as the key to a valid contract here.

Interesting discussion. I wish I was more up on contract law.