Everything comes down to money. The SEC doesn't hedge on FSU because of brand. FSU's football brand is as big or bigger than most schools in the SEC. And they've had more success too in the last 30 years. Why would the SEC be more interested in UVa than FSU? UVA would bring a new TV market to the conference which would mean more money in future contracts.
FSU doesn't want to leave the ACC because they missed the playoffs. If their QB didn't get hurt they probably go into the playoffs as the #3 seed. And next year the conference champion gets an auto bid to the playoff anyway. Who do yall think is going to be predicted to win the ACC next year? Them dudes are mad about the money. They want the same kind of money schools in the SEC and BIG 1G are getting and this is their only play because the ACC isnt up to renegoaite the contract with ESPN for a decade.
Follow the money.