Why have so many post-industrial Midwestern Small Cities experienced large Black influx 1990-2020?

[I spent the winter writing songs about getting better]

This is kind of a modern day smaller scale Great Migration. Although I think the OP is actually talking about two completely different sets of cities where the reasons would also be completely different.

Take those Minnesota and North Dakota ones that I'm most familiar with. All of those cities have features that would attract people in general, strong job market, good schools, low cost of living (relatively speaking, especially in ND it's gone up significantly in recent years, but still lower than major metro areas), low crime (again this too is relative, crime in ND has massively spiked compared to say 20 years ago and is a serious concern now because most cities in ND don't have the police or legal resources to handle it....but these are still places where carjackings and drive-by shootings are pretty rare, same with the outstate Minnesota cities although they started with higher crime rates and thus haven't had quite the surge), so people in general flock to them, and this includes lots of black people fleeing those things, from the Twin Cities metro but also places like Chicago. Although I think the initial premise is incorrect in regards to those cities, those aren't post-industrial places or economically blighted and "no economic opportunity and smaller pressures of unaffordability" definitely doesn't describe them that well.

I think the housing bubble and subsequent recession was a factor too, Rochester was known to not be hit too badly by this and still had a pretty solid economy even from 2008-2010, same with the ND cities thanks to the oil boom, and St. Cloud and Mankato are college towns that are to some level recession-proof, so these were good places to get situated during that time. But again that kind of shows they don't fit in the premise of the OP, they're really the opposite of post-industrial economically declining areas.

[I spent the winter writing songs about getting better]

This is kind of a modern day smaller scale Great Migration. Although I think the OP is actually talking about two completely different sets of cities where the reasons would also be completely different.

Take those Minnesota and North Dakota ones that I'm most familiar with. All of those cities have features that would attract people in general, strong job market, good schools, low cost of living (relatively speaking, especially in ND it's gone up significantly in recent years, but still lower than major metro areas), low crime (again this too is relative, crime in ND has massively spiked compared to say 20 years ago and is a serious concern now because most cities in ND don't have the police or legal resources to handle it....but these are still places where carjackings and drive-by shootings are pretty rare, same with the outstate Minnesota cities although they started with higher crime rates and thus haven't had quite the surge), so people in general flock to them, and this includes lots of black people fleeing those things, from the Twin Cities metro but also places like Chicago. Although I think the initial premise is incorrect in regards to those cities, those aren't post-industrial places or economically blighted and "no economic opportunity and smaller pressures of unaffordability" definitely doesn't describe them that well.

I think the housing bubble and subsequent recession was a factor too, Rochester was known to not be hit too badly by this and still had a pretty solid economy even from 2008-2010, same with the ND cities thanks to the oil boom, and St. Cloud and Mankato are college towns that are to some level recession-proof, so these were good places to get situated during that time. But again that kind of shows they don't fit in the premise of the OP, they're really the opposite of post-industrial economically declining areas.

Yeah, I knew the MN and ND cities were different, just included them because they also had huge increases in Black population.

You are most familiar with Minneapolis, for example. Would a typical person working 'unskilled' labor be able to have a higher standard of living in Bismarck than in Minneapolis? The reason urbanization occurs in the first place is that higher wages in cities outstrip higher living costs. Perhaps at the minimum wage level it's the case that life in Bismarck is easier than Minneapolis though.

However, the fastest increases in Black population came between 2010 in 2020 in MN and ND. During that period, the old minimum wage became outdated for Minneapolis and even the lowest skill jobs surely pay better in Minneapolis than in Bismarck. Now Minneapolis has a $15 minimum.

That last part is actually not true. Even retail jobs in Bismarck are having trouble hiring. The minimum wage is a lot higher in Minneapolis, but I bet the Target in Bismarck probably pays about the same as the ones here.

Speaking as someone who actually fled Bismarck for Minneapolis, it should be obvious what I prefer, but in terms of things mentioned above like crime rates and schools which impact black families way more than me, it's obvious which city would have a higher standard of living.

One thing I know for sure: gig work is more lucrative in Bismarck. It has far fewer per capita DoorDash and Lyft and Uber drivers...I made $48/hour in one stint in Bismarck. During an evening NFL game, but regardless. And Lyft and Uber are always in high demand there.