The upcoming 'All In' event from Chicago hasn't even taken place yet but there is much speculation about the next event which will be presumably be called 'All In 2' with rumor pointing toward the event being hosted at the legendary Madison Square Garden in New York City.
This rumor of course sounds amazing but there are a couple of reasons why this might not happen.
Historically WWE has had a hold on the arena, for those that don't know New York City is a traditional WWE territory dating back to Vince McMahon's Father and Grandfather. WCW made a play in the early 2000's to host an event there but were successfully blocked by McMahon.
Despite this, Dave Meltzer of The Wrestling Observer recently revealed on his website that WWE has lost its hold on the building and any promotion could potentially run an event there and there is an event date (not WWE) on hold there but due to the high rent rates it would be unlikely they could afford to run it or sell it out unless they make ticket prices extremely high. WWE now only do live events there, and any indy promotion considering hosting an event would have a lot against them and the potential for McMahon to swoop in and poach key talent before the event.