In fact, if there's any 'death spiral' in cities to speak of, it's the one caused by the War on Drugs and tough-on-crime policies which have led to mass incarce

In fact, if there's any 'death spiral' in cities to speak of, it's the one caused by the War on Drugs and tough-on-crime policies which have led to mass incarceration. People in low-income areas have few income options. They turn to illegal activities to make money. They then get incarcerated for those activities. That then removes those income generators (illegal as the income may be) from the community, which in turn impoverishes the area even more. Go to beginning. Unfortunately there's no immediate fix to this but at least it does seem that there is starting to be more bipartisan agreement that the current mass incarceration system doesn't work.