I don't see how limiting availability would translate into better ratings. You're limiting your potential audience by doing that.I thought I remembered hearing about how the NFL wants Sunday Ticket to be exclusive to one provider too. I seem to remember reading that they wanted to limit availability of Sunday Ticket to keep the Networks' games in demand with good ratings.
I've been under the assumption that the NFL can demand more $$$ for the exclusivity, thus bringing in more revenue than if it was available to all providers....