The new Yankee Stadium was built on a local park, and part of the deal was that they replace all parkland that was lost in the neighborhood. The city would never agree to go back and renege on that deal, as it would be much too politically toxic. There's barely any decent space around there that they could try to pass off as a viable swap to replace the as-is replacement park either.
if we can't create space in the Bronx for a new park then I don't see how we create any space for a stadium. Maybe it was foregone conclusion that the Bronx could never happen. As a newcomer, it's still disappointing.