This is actually very interesting. All we've been hearing about is how MSG had an attendance clause and/or some other out of the BE contract. Now, from Thamel's article above:
The ACC has no chance to move to Madison Square Garden in the immediate future, as MSG has a deal signed with the Big East through 2026. Multiple sources described that contract as "air tight." A source with direct knowledge of the contract said that Joseph M. Leccese, the Big East's lawyer with prominent firm Proskauer Rose, spent an inordinate amount of time making sure that MSG couldn't get out of the deal with the Big East.