The reality on the ground is that a larger percentage of frum Jews in America are consolidating in centralized areas such as the greater Lakewood area, the greater Monsey area and the greater NYC Metropolitan area. Lakewood, especially. But even the frum Flatbush community was growing until about 15 years ago or so. Nowadays it is mostly Lakewood and Monsey.
But what is happening out of towns is that many frum communities OOT are either shrinking outright or stagnating. This is because the young frum (chareidi) couples from out of town are moving to Lakewood in significant numbers shortly after their weddings.