I helped build that ASSembly Hall! Actually, the teenagers I went with...we all sat in someone's car and listened to Rat "Round anI'm d Round" and Prince "Purple Rain" Both were not on the JW list of most acceptable music! I can't remember if we were just lazy teenagers or if there was nothing to do. I remember going into the Hall to see it, and going down there once it was nearing completion just to see it inside. I left the religion about the same time as the assemblies started there driver.
I think it really is lack of donations and another site close-by in the next county Palm Beach. I "bet" the WTS self-insures the building and property taxes are cheap due to it being a religious facility. If costs are not a problem, then it's revenues. And, that's a good thing!
The Watchtower can always go back to renting out the Gulfstream (Horse) Race Track in Hallendale Florida. I remember those assemblies. At least, we got to look out at the center of the track that was beautiful green grass with lots of plants, dream of the winner's circle, and walk around the beautiful gardens. You could also see the blue waters of the Atlantic and Intercoastal if you sat high enough in the grandstand. Made the ASSembly somewhat enjoyable.