I stumbled across the documentary 'Detropia" on Netflix a few weeks ago. In short, it was really disappointing and tough to get through. Why? Andre Seewood nails it at Shadow & Act:
The film, DETROPIA, while trying to put Detroit's decline in a larger nationwide context of the erosion of manufacturing plants and outsourcing fails to mention or put into perspective the racial tensions that have long defined Detroit, segregated the mostly Black populated city from the mostly White populated surrounding suburbs and severely undermined the Black political power base that used to govern the city.
Seewood gives a pretty exhaustive critique, which you can read in full over at Shadow & Act.