Middle class black families don't want to (really: won't) move into a city with high crime and low employment prospects. We attribute a racial dynamic to Detroit because of the label "white flight", but it's the label that's racist; the dynamic transcends race.
You see the same thing in Oak Park, on the outskirts of the West Side of Chicago, where I live. If you can get out of Humboldt Park and North Lawndale, you do: the schools are better and the neighborhood is safer. And the move from Lawndale to Oak Park doesn't even change your employability, unlike a move out of Detroit.
Exactly that; Chicago has a diverse economy that isn't as dependent on manufacturing; Chicago is also a finance center and a transportation hub, neither of which hurt.
It's not really just the label that's racist - I wish I could hand you the citation, but I'm having trouble finding it online. IIRC, there was a study dating from the 60s that showed that when a neighborhood reached somewhere around 10-15% black, white people started moving out. This was taken advantage of by real estate investors, who would move a few middle-class black families onto a block (possibly taking a loss, because completely white neighborhoods aren't attractive to most black families), starting a process of buying at a discount the houses of the white families who were desperate to leave, and then reselling to middle-class black families who often had higher incomes than the white families they were replacing. In this way, the replacement of white families by black families would snowball.
Of course, the appeal of those neighborhoods to middle-class black people would also drop, because as the whites left, the neighborhood lost its luster as a symbol of achieving the middle-class for black people. Prices start to drop to the level where less than middle class people can move in (to what would still be an aspirational neighborhood to black people who weren't in the middle class.)
Then the city starts to withdraw services (the 1950s, 1960s, 1970s city), and, as in Chicago for example, builds highways and other developments as firebreaks to stop the expansion of these new black neighborhoods. Eventually many sections start to go into serious decline, and middle-class black people either leave, or manage to form exclusive enclaves within them.
tl;dr Humboldt Park and North Lawndale didn't originally have high crime and bad schools, that was a process that was begun by white flight.
I always like to cite the example of the neighborhood I grew up in in Chicago: Avalon Park, where "the average educational level increased, while the poverty rate decreased from 6.1% to 5.1% between 1960 and 1970."[1] The fact that black people were an improvement to the neighborhood didn't slow white flight down a whit - we moved there in 1978, when I was 2, and when I entered school at 5 there was a single white person that attended Avalon Park Elementary School. His name was Patrick, and his stepfather was black. I only ever saw one white person in that neighborhood who wasn't a teacher at that school. It was a windy day, and she was walking in front of Sears on 79th, trying to keep her scarf from blowing away. It was 1989.
If you care, I'll find the reference at some point - but I couldn't find it online, and most of my books are packed away in a fashion where it would take me at least an hour to find anything specific. If this year is like last year, I'll find cause to wade into the stacks two or three times and I'll keep an eye out for it.
That's also true, but on the flip side I think what we're seeing in Chicago is that the middle class black folks are more reluctant to leave for the suburbs and try to stick it out longer in those neighborhoods than the middle class white folks.
You see the same thing in Oak Park, on the outskirts of the West Side of Chicago, where I live. If you can get out of Humboldt Park and North Lawndale, you do: the schools are better and the neighborhood is safer. And the move from Lawndale to Oak Park doesn't even change your employability, unlike a move out of Detroit.