FSU thinks their a brand, like Alabama, that gets national eyeballs just because they're on TV. Clemson is pretty close to a brand that adds eyeballs because of their recent success. UVA and UNC are at best a market addition and don't really add many eyeballs. The SEC has enough marquee names to have the 3:30 and the 7:00 game attract attention from all over the country. That's what Clemson adds that South Carolina never will and that's what FSU thinks they add. The SEC would take Clemson in a heartbeat and maybe FSU. But at $70m to $100m a school, do UVA and UNC add that much value to either the SEC or the B1G?
At some point the SEC and B1G have to be thinking, "can we just jettison Miss St. and Vandy and have a conference of just blue bloods?"