I believe it is being done for several reasons, the main two I will list here.
The properties are just worth too much to be running factories and housing Bethelites in. It's like San Quentin Prison. That property alone is worth millions if they just tore the prison down. Developers would be tripping over one another to build condos on such prime bayfront property. A new prison could be built in a much more remote location on land that is insanely cheap. CT Russell moved to Brooklyn to put an international stamp on his movement. That has already been achieved, and nowadays in the information age you don't necessarily need to be running things out of a huge metropolis to get noticed. The cost of living is much cheaper where they are headed to. Straight up business decision.
For all their apocalyptic rants about the Great Tribulation and Armageddon, New York is the last place I would want to be if I believed what they believed.