Re: Notre Dame football...
I believe NBC renewed the contract already, but may be remembering wrong.
Anyway, I think the answer is that TV contracts are controlled by conferences - i.e. the SEC has a deal with CBS for Saturday afternoon games - and since ND is not in a conference as a football team (yet were able to weasel their way into the Big East in all other sports), they basically control their own TV schedules.
Their deal started maybe 10-15 years ago, so if it was against NCAA rules or anything, somebody would have complained by now, but with the way TV arrangements are now handled, their deal is perfectly fine.
That's how I understand it anyway.