It's not the same legal situation as Maryland, Texas and Oklahoma. All of those schools had exit fees established in their conference contracts. None of them had a clause that said "If we join a conference, it will be the ACC."
You are also correct about the GOR. All of those long-term TV contracts (ESPN, ACC Network) are based upon the top brands playing the schedules that they promised. If ND vs FSU is no longer available, the ACC can't backfill that game with Wake vs GT and keep the same viewer audience.