Detroit seems to be turning the corner at the bottom of a decades-long economic slide, but there are also some interesting long-term environmental trends that I think bode well for it and many smaller rust belt towns. Most pressingly, a lot of those towns are directly on arterial waterways and receive copious amounts of rain. So you get extremely cheap transportation of goods, and you also just have a water supply in general.

There may have been a great migration to the Southwest over the last 40-50 years, but it's hard to picture a scenario where that area's ecological budgetary chickens don't come home to roost at some point. Then, Detroit and other communities like it become significantly more attractive.