Can the Mets actually not close the deal?

Santana's agents, Peter and Ed Greenberg, are believed to be looking for a six-year extension in the range of $150 million -- a figure that would include an upfront payment that would boost Santana's 2008 salary ($13.25 million) to beyond $20 million.

Buster Olney blogged yesterday about the incredible leverage Johan wields in this case. The Mets knew this. Will the unthinkable happen?

Could this resemble another landscape/history changing deal that also failed to reach the finishline? Could the Yanks swoop in if the Mets deal fails, offering the deal that they'd want to do, and steal Johan, just as they did with ARod in early 2004? Could you imagine?
I highly doubt the Mets fail to sign Johan, so it's nothing more than a fun exercise in "what if's". But, WHAT IF!?!?