Without knowledge of NBC/CBS/Fox's internal balance sheets, this seems unlikely.I'll concede that I don't know them any better than anyone else speculating on the matter, but I know for sure that all three networks get a per subscriber fee from cable companies like any other channel on cable.
The NFL has 15-16 games per week. Of those, 4 or 5 are on the local broadcast (three or four on CBS and FOX, one on NBC in the evening). If you want to access the other 11 games, you're reliant on cable-based access.
And the NFL is a unique animal here. MLB, NBA, and NHL are all completely reliant on cable-based delivery methods.
The sports networks these companies have launched are all fledgling and receive a miniscule subscriber fee relative to ESPN.
Fox Sports is not fledgling. They've been number 2 to ESPN for most of their history, and a huge number of NBA and MLB games are broadcast on Fox Sports.
Sports as an industry clearly needs cable subscriptions to support its current business model. And those cable subscriptions are reliant on people that don't watch sports paying for them anyway.
Eventually the sports industry is going to be forced, one way or another, to deliver a better user experience, and it's highly questionable whether or not they'll be able to generate the same revenue without the support of non fans that cable brings.