Broadcasting rights isn't the NFL's only source of income - it's not even close. By last calculation, DirecTV was actually losing money to retain their NFL rights. They overpaid the NFL badly so they could basically remain in business.
This isn't a matter of "Big" anything. DirecTV forced its competition out of the market with the NFL as a willing accomplice. In my world, I call this an ill-gotten monopoly and artificially controlled demand. DirecTV did not earn exclusive rights by providing service better than any of their competitors. They simply bought it.
What, it's your position that DirecTV couldn't remain in business without Sunday Ticket?
Kind of makes you wonder how Dish Network is able to keep the ship afloat without Sunday Ticket, considering that it's pretty much the exact same service as DirecTV.
P.S. Manufacturers are entitled to enter into exclusive dealings contracts. They do it all the time. Sorry if you don't like it, but it's the free market in action. Deal.