Obviously we do not know all the details and that makes it dangerous to speculate but:
If the information we have now is correct about the reduced buyout, keep TV rights if leave after certain time etc.; then there was something giving Clemson and FSU major leverage.
For all the talk of how ironclad things were the ACC sure did give up what appears to be a lot.
Could have been several things: -Other schools (UNC?) were also threatening to leave risking conference implosion -ESPN put pressure -There was some bad acts on ACC's (individuals) part they didn't want to come out. I mean there was a reason John Swofford was specifically mentioned in the lawsuit. HMMM, may be a little more fire than just smoke when came to his son's work with Raycom, etc.
In over 25 years in legal profession I have had a lot of clients in family court say they are ready to fight. Then the PI pictures of them meeting their girlfriend show up ....and well things change.