The auto companies provided the wealth to fund the socialist policies in Detroit(along with federal taxpayers). The auto companies poured billions of dollars into Detroit revitalization. Minority supplier set asides, The Renaissance Center, the GM investments near their headquarters and many other billion dollar give aways were literally spent to try to help Detroit.
This was in addition to the tax dollars paid by auto companies, their suppliers and their employees.
This money was wasted and stolen by the politicians. They encouraged criminals and welfare recipients and made life unlivable for honest families to live.
In the 1960’s Detroit was by far the wealthiest city in the world. That wealth allowed the politicians to survive for decades while they plundered the city. They have now run out of other peoples money.