Actually, it's an interesting Catch-22 for ESPN.
First, if ESPN were to actually and effectively argue for the "we own your rights until 2036" position, that would mean that...they actually plan on honoring every word, every punctuation mark, and every space in the original contract.
On the other hand...I highly doubt that ESPN would honor a contract with the ACC after the 8 best teams leave.
Second, here's a very interesting thought experiment...if the BASIS for the monetary "damages" in a GOR case is "well, you forfeit the payments", then what would it mean if...ESPN wants to pay the ACC a lot less money. Bear with me for a moment. If only TWO teams left the ACC, and two replacements were found, then it is POSSIBLE that ESPN could give us the Pac 12 treatment ("we will honor the contract even though you just lost two teams"). But what happens if ESPN decides to pay the ACC less money than before. Now, any additional teams that leave...would be walking away from LESS money, so the argument can be made that this is no longer "35 million times number of years remaining".
This stuff is crazy.
Bottom line, I'm completely in favor of 8 teams giving notice, but I'm not yet QUITE convinced that the Power 2 plus the Big 12 are ready to absorb everyone. People underguesstimate how much alums of the Big 10 (and SEC) schools are already agitating towards their Presidents and ADs about expansion, and how it is "destroying" college sports, even though we all know the real reason is that a lot of people want to maintain the "exclusivity" appearance of their particular conference.