Cars destroyed rural America. Take a Youtuber like Hoovie's Garage, he buys a large farm in the middle of nowhere to store cars, drives regularly a 100miles a day. You can't have compact European style towns, in such a reality. The factory closed, people drive 60 to a 100 miles a day, that means that the town is flattened and gone.
Add to that oil disease in places like Kansas, Texas and W. Virginia; the government doesn't need to have sound businesses as a tax base to fund itself, just oil money.