I don't know how often, but towns existed because they supported the surrounding Agricultural families. They were content and even happy. Then Industry came to town, perhaps because the land was cheap, taxes low, and the local governments were sold on the Prosperity Doctrine (like so many false Christian preachers grift today.) After they we used up like an old whore they left a town that was top heavy and unsupportable. Right? It's the way of the[modern] world...