On Monday, the presidents of the ACC school approved a grant of media rights for the conference through the 2026-2027 season. What that means is that until the expiration of the contract, each school's media rights (revenue included) for each home game will remain with the ACC, no matter which conference the school is a member of. For example, if UNC jumps ship to the Big Ten, all of their media rights revenue will end up in the coffers of the ACC as opposed to the Big Ten.
Essentially, what this agreement does is ends the possibility that other conferences will be able to poach schools from the ACC to expand. The Big Ten, Pac-12, and Big 12 all already have these agreements in place, but oddly, the SEC doesn't have one (yet). So for any conference to expand, they'd need to look at the mid-major conferences: the AAC, MAC, Conference USA, Mountain West, and Sun Belt. The SEC remains in play for expansion, but I think it goes without saying that it would take an act from above to make a team bail on that conference, especially with the pending announcement of the SEC Network.
If any conference was looking to expand, their options are slim with the ACC conceivably out of the picture, as if the new $52 million exit fee wasn't enough reason for a school to leave. Geographically, the Pac-12 probably has the best options for expansion, with Boise State and BYU both looking like pretty solid options despite their commitments to the MWC and independence, respectively. The Big 12 has SMU, Houston, and Tulsa nearby to poach from the AAC, while the Big Ten and ACC would seemingly battle for Cincinnati, UConn, and perhaps even Temple. UCF and USF could also draw interest from the ACC.
The lone conferences that look safe from any more poaching are the MAC, which has been relatively stable during the realignment chaos of the past few years, and the Sun Belt, which has experienced so much turnover in recent years that it's essentially become the conference where all of the unwanted teams across the country end up.
It looks like that the era of realignment has come to an end, at least when it comes to the big name schools that could move the needle in both football and basketball. You're not going to see anymore long-term rivalries get destroyed in the name of the almighty dollar, and that's probably good for the health of college athletics as a whole.