It might also destroy the NFL. College football is NFL's golden goose, they're not going to **** with that so long as college football remains a feeder league for the NFL rather than a competitor.
Nothing is destroying the NFL. The average NFL reg. season game was 17 million. The two BEST CFB games (outside of playoffs) were 10 and 15 million. Keep in mind there are prime time slot network college games that barely break 1M.
I also don't think NFL is too scared about losing it's feeder league. What else are college players going to do? It's not like CFB would disappear, it will just take a beating in ratings, and ESPN and Fox lose money.
The National games on network TV in the NFL typically get 15-28M, with the top being 38M! Now, the NFL network games and the Fox/CBS games that are doubled up and regional tend to get 7-9M. So basically those games' viewership gets cut in about half, which makes sense.
If you open up slots for 3 games on Sunday, that would mean almost every game CBS has is national, with what, two being regional and sharing a slot? So, due to CFB competition you don't just double viewership of what would've been an otherwise doubled up regional game. But you wouldn't have to for it to make sense financially.
Now, who knows if the NFL would allow it, but if CBS stays out of CFB, that would be the first time since the very early days of Fox's NFL coverage where there was an NFL-carrying network that did not have college football.
With that said, I don't think it happens.