Sugrue's "The Origins of the Urban Crisis" has a much more nuanced thesis, and part of it is that people were leaving well before the 1967 Uprising, part of it was broader economic changes, part of it was governmental policies (especially with regards to housing and transportation).
The causes of the decline of Detroit's population are complex, not something that can be distilled in an HN comment honestly. But the idea that no one left Detroit willingly is not correct. I know people who did, even interviewed someone who said their family left due to simple racism: a Black family moved to their neighborhood so they left. Of course, in many cases choices could be weighted by other things like, say, you wanted to purchase a house but couldn't get a mortgage in the city due to extensive redlining but could easily get one in the suburbs.
My family left the city in order to raise children. We tend to forget that cities can turn bad fast when there is an economic crash. They are the first places to be hit with drugs and crime.
The causes of the decline of Detroit's population are complex, not something that can be distilled in an HN comment honestly. But the idea that no one left Detroit willingly is not correct. I know people who did, even interviewed someone who said their family left due to simple racism: a Black family moved to their neighborhood so they left. Of course, in many cases choices could be weighted by other things like, say, you wanted to purchase a house but couldn't get a mortgage in the city due to extensive redlining but could easily get one in the suburbs.