While I essentially agree, Detroit's downfall is that they did not adapt to the changes. The UAW employed so many people in the area which built up a lot of the middle class. The requirement to join the UAW and make $25/hour starting in the 90s working on the assembly line was a GED. If you had that, you were in. Well, those jobs now pay $14/hr starting and a lot of the supporting companies went under or streamlined their process to employ less, create less waste, and be more efficient.
There are still some really good jobs in Detroit and nice areas to live. Many of the suburbs are really nice and are doing well. To scale Detroit though, you have to realize the city limits of Detroit are larger than NYC and two other major cities. I think it was DC, NYC, and Boston combined are around the same size as what Detroit once was. When we have 10 million people disappear in 20 years... that leaves nothing but a vacuum.