If it does happen if will be the deathblow to both nyc nightlife and many of the main employing industries in the city. People might be tempted to leave their jobs particulary if they dont get out till 1am in the morning. They wont get the chance to partake in nightlife, what are they going to do simply not go out or ask to a transfer where the closing time is 2 and the office hours end at 8. Its also unlikely that new venues will open up with 2am closing on the license they cant compete with the venues open till 4am.
It will happen and worse than that i wouldnt be suprised if bloomberg makes all bars close at 2 just to shut them down all because they cause slight amounts of crime in his virtually crime free manhattan. At best no new places will open up they wont be able to compete with the existing places that stay open till 4. Its only a matter of time before licenses come up for renewal and wont be granted for 4am closing and a result that establishment will close. People wont risk their money opening new places under these conditions.