A bell building like that almost certainly housed a large telephone exchange. Demolishing the building and then building a new one would likely require a temporary exchange to be installed somewhere else. Moving the existing building, and keeping it operating during the move, then building the new building would make it possible to transition the circuits to new exchanges built inside the new building with a minimum of downtime over the next 33 years.

And probably an entire floor or more of the building was dedicated to flooded lead/acid batteries for uninterrupted power to the telephone network.

Indeed, sadly that is mostly gone and buried now. Before the phone company was basically completely responsible for keeping your phone working.

Now keeping your phone working requires both parties, the vendor and the customer to keep stuff happy to make the phone work.

Yes I've visited the battery banks in make exchanges in the Netherlands in the early 2000s. Phone exchange equipment runs on 48V DC for this reason. I've even been to relay-based phone exchanges that still existed in those days, though they were rare. Pulse only. It was weird being in a dark building sounding like it was infested by crickets. Really spooky.

Is this conjecture or fact?

Why make stuff up?