In the early '70's, shortly before 1975 (the big day was supposed to come), Watchtower was expanding its New York facilities. They purchased the Squibb Building, raising a red flag in the eyes of many. No excuses were offered except that it was "Jehovah's will.
https://www.syracuse.com/state/2015/12/jehovahs_witnesses_could_get_1_billion_for_nyc_properties.html
The Witnesses bought their 733,000-square-foot headquarters from Squibb Pharmaceuticals for $3 million in 1969. It was placed on the market this month along with a nearby apartment building and a 135,000-square-foot lot. Despite the prominent "Watchtower" sign, the building has no historical designations that would place restrictions on the buyer.
There's big money in real estate, apparently even after Armageddon
The final large property to sell was the former Squibb plant, adorned with the Watchtower sign. With the final move of 800+ Jehovah’s Witnesses residents and staffers to Warwick imminent, the sale closed in 2017 for $340 million. While the organization still holds a few smaller properties and garages in the area, a few of which have sold since, the sale of the Squibb building served as the final goodbye to Brooklyn.