It also heavily depends on the customers you are selling to in Detroit. Basically all state/local government agencies and a large percentage of big local business have "minority owned business" preferences written into their purchasing process. As a result, you'll find a number of small shops whose sole purpose is to be owned by a minority and then subcontract out jobs to other companies who might not otherwise be able to compete for those contracts. Alternately, I've encountered companies entirely staffed by non-minorities but the company is "owned" by the wife of the CEO who happens to be Asian or whatever.
Michigan has a Disadvantaged Business Enterprise (DBE) certification process to attempt to reign in some these shenanigans (used by MDOT for road construction projects) but I still see this sort of thing all over the place.
I'm not sure about numbers of those business, so I can't really speak to how prevalent that is, but I'd imagine that sort of fraud is pretty small in both number and dollar value compared to the higher-profile and the larger tax breaks given to the Ilitches and the like. There just isn't the same amount of money going to minority business owners/neighborhoods vs. white business owners/white(r) neighborhoods in a city that is 92% Non-white.
Michigan has a Disadvantaged Business Enterprise (DBE) certification process to attempt to reign in some these shenanigans (used by MDOT for road construction projects) but I still see this sort of thing all over the place.