No! Some people are too poor to move..or have jobs, elederly relatives or disabled partners to take care of. then there's the real estate issue - where selling and moving would cause added mega-losses that are prohibitive.
There are many reasons why someone can't move from such depressed location. Take the residents of N.O. Lousiana pre-Katrian. They couldn't move from Katrina's destruction. No car, no money.
Actually they can move.
You're correct that for some people moving presents great difficulties, but they can move and they would if a rampaging army was on the outskirts of their city.
The sad truth is that for most, although certainly not all, of these folks their perceived lack of choice is the culmination of a series of bad choices made throughout their lives.
Thirty years ago Detroit was a pit.
If 30 years ago you made up your mind that you were moving yourself and your family from that pit, you would have done so by now.
Perceiving these people as helpless victims does them no favor.