Ten years ago, the area I lived in was splitting congregations and each one had a full capacity. Property was expensive and no new plans for additional Kingdom Halls in the entire circuit were planned. There were new halls in nearby circuits, but property was out of reach in our area. The elders from several halls were looking for a new place to build a double hall and were getting close to figuring the finances. But squabbling between the different BOE's kept it from becoming reality. Everyone just stayed in their crowded halls.
The English cong. I left years ago had 3 English congregations, and 2 foreign-language congs. The foreign Lang. congs. moved out closer to their own populations to allow the remaining ones room at the hall.
My old congregation had been splitting over the last several decades, feeding many other new congregations with members. It seems to have turned around a few years ago. One of the congregations was so small, the C.O. kept recommending they dissolve and go into the other two. Their BOE was stubborn and didn't listen. The C.O. never recommended it strongly enough and didn't send the recommendation to WTS, figuring that shrinkage looked bad. As long as they could struggle on their own, he left them alone. Finally, the other larger congregation decided they didn't have enough elders, and the stubborn elders liked their positions in the smaller cong. so the larger cong. dissolved and incorporated into the other two, but largely into the smaller one. That way, the title-loving elders could keep their positions and be in charge, and the other cong. could just join them.
Anyway, the point is that the new double hall never happened. It certainly is not needed now. All the halls are still there, and making the monthly bills, but they are close to the point of selling off more property. It seems that each hall is down to 2, some 3 congregations, but there are a few with only 1 congregation. They are ripe for WTS's need for money. Too bad (for them) they missed the real estate boom- the money will be much less if they don't wait for several years now.