Eh. Nielsen-rated viewership is definitely a big draw in the streaming world. But still, even as cable continues to decline, carriage fees are a LOT of money on the table.
Those of us who watch the ratings know that Nielsen ratings are a self-licking ice cream cone. FSU can tout how much higher its viewership is because it's on the major networks for a lot of matchups. And it gets those matchups on major networks because it has high ratings.
I think the conferences definitely look at Nielsen-rated viewership - but their commissioners are smart enough to discount it as a sole factor, or a single question. It's that, it's carriage fees, it's fanbase, it's type of university, it's geographically-favorable location, it's AAU status. It's all of the things I've mentioned here, and more.