the linked article did mention apartments were “abandoned”, so maybe it is actual organized crime local to NYC. They would have to at least be pretty entrenched to know where is safe to set up.

If it were just run of the mill spam/scam stuff, why not just use VoIP or contract out like the rest of them do? It would certainly be cheaper if that were the goal. There are many, many different reasons to want so many local numbers that are beyond the obvious. Personally, I have questions.