Not saying these places will universally recover, or even any of them will. There are plenty of secular trends pushing industry to other places. I do think decades is rightly considered short term for city history, though. At various periods in Paris, it's been laid to siege by viking hordes, had its population cut in half by Black Plaque, been occupied by Nazis, the student protests of the 1960s. Still seems to have done all right over the long run of centuries. Doesn't do much for individuals with bounded lifespans and I know that's mostly what we care about as individuals, but the world and arc of history are a lot bigger than us. None of us will ever know what becomes of Detroit in the 22nd century (unless there are 5 year-olds reading this thread), but there are plenty of reasons it may end up a booming metropolis that makes something other than automobiles and the greatest R&B ever put to wax.