I would argue unions in particular destroyed Detroit, it's arguably even less complicated than Baltimore. I think there was ~13 major auto factories in Detroit

I would argue unions in particular destroyed Detroit, it's arguably even less complicated than Baltimore. I think there was ~13 major auto factories in Detroit at one point, and what would happen is when the UAW would protest, they'd leave one factory and go to another, more important factory (often wherever they were producing engines) to apply pressure. The result is auto makers were forced to build new factories outside of Detroit, first in other MI cities and eventually in other states and countries. Now I think there's only ~three factories in Detroit, including for products that aren't really that exciting like spark plugs. I didn't realize so many cities were referred to as an american Paris though, that is interesting. It was, certainly however, a beautiful city at one point.