If a majority of schools in the league vote to disband the league then the grant of rights doesn't apply.
What if Virginia, VT, UNC, NC State, Clemson, GT, Fla. St, and Miami wanted to disband the league to go to the SEC.
SEC would be at 24 teams. They could figure it out from a scheduling standpoint.
TV money is what is important. If the ACC disbands, then the ACC network and all of the ESPN money goes bye.
ESPN also holds the rights to the SEC. So the ACC money is now spilt 14.5 ways with Notre Dame getting a small share. ESPN could plow that money back into a new SEC contract paying the new SEC teams the same as the current SEC teams.
I haven't done the math but it has to be lots better than adding new teams with no incremental revenue. The 8 schools coming in could bring the entire current ACC revenue stream to the SEC.