And they will sign a new deal with the new place that most of the teams land. There are only so many landing places in the existing conferences. FSU wants to go to the SEC, they'd probably need a buddy to go with them. Who in the ACC makes sense for that? For TV it's probably Carolina or Duke but I can't see the two of them voluntarily splitting up. For football it's probably Clemson but that doesn't add the most TV money. Possibly Miami but they don't really fit into what the rest of the SEC is school wise and IDK if Florida would be super keen on having both FSU and Miami in conference. Virginia theoretically gets you the DC TV market. Syracuse and BC are non-starters.
I think the ACC could survive without FSU and Virginia. You'd see them pick up UCF to keep the Florida footprint maybe court WVU away from the Big 12, maybe lean on ND to become a full member.
I don't think UNC walks away from Duke. I might be wrong, but UNC in the SEC would be a perpetual bottom dweller in football and they'd lose a lot in basketball. What they might make in added TV money for football, they'd risk in losing bowl eligibility basically forever.
Clemson and UNC are state schools btw.