It's hard to imagine anything on that scale. Centralia PA (former pop. 2600) was deserted due to major underground fires. But real cities have bounced back from far larger disasters. Hiroshima lost 2/3 of its population but recovered in 10 years.

Remember, though, the actual city of Detroit is only 1/5 of the population of the metro area. While Detroit is failing, the metro area is only hurting. It won't be abandoned.