Not gonna happen

Normally I'd agree with you, but Citi signed a contract with the Mets two years ago.  It's a done deal already.  If Citi tried to back out, the Mets would sue the pants off of them (assuming Citi has any pants left).  Signage has already been bought, paid for, and installed.  It would take time for the Mets to find a new naming-rights sponsor.  You can't just change your mind and say "no thanks."