What happened in Detroit was a result of a decline in manufacturing after the end of WWII, white collar types spreading out to the suburds and the auto industry spreading with them, increasing automation replacing assembly line workers, crippling Union lead strikes giving the auto industry reason to depart from the city - finally heading to Southern States and later Canada and Mexico, business centered around them shutting down, riots, the energy crisis of the 70s causing car sales to slump, declining auto market share as imports took over in the 80s, mortgage redlining preventing poorer folks from moving to the burbs or opening their own businesses and thus getting stuck in decaying slums, former factory grounds being so polluted that building anything else upon them would be diifficult and costly, etc, etc, etc,,,
Corporate welfare enabled its own decline in Detroit's center by financing its departure to elsewhere, utilizing subsidies and tax incentives to move abroad in search of cheaper labor.