Redlining was basically part of the law, as FHA historically required higher down payments for “less desirable”, aka non-white neighborhoods.
In the countryside or exurb, a similar dynamic arises... “the wrong side of the tracks”. Even without the racial dimension, the trailer parks and the horse farms tend to be in easily identified geographically distinct areas.
In hot markets in my area it’s easy to see. The “desirable” areas surge ahead of the baseline tax assessment comps, and the “undesirable” do not. You can map it in a stable area and it lines up with the old FHA maps.
Decades of a market like that leads to those conditions staying around for awhile. As multi-family real estate is getting appealing to people with money, I think we’ll finally see that legacy fade away.