[1]: I don't live in Michigan any more, but I do visit Detroit regularly.
I was shocked at how bad Detroit actually was. In my opinion, it's actually worse than what people say. A story I heard from one of the people that live in the area is that people leave their cars unlocked and devoid of valuable belongs so crackheads won't break their windows to search for money. They're still going to search, but they won't break the windows.
The areas being gentrified by young professionals that would be considered "Detroit" are concentrated in the Downtown and Midtown districts. Hamtramck is in the gentrification process as well, but it's considered a separate city.
Basically the fact that the newly-relocated white collar workers are all spread out and are offset by the mostly blue-collar old guard likely explains why it wouldn't make the top of the "Brain concentration" index.
Ann Arbor, on the other hand, makes more sense because its geography is so much more centralized, and is only supported by a few bedroom communities (Dexter, Selene, and Chelsea)
Small metro areas that are dominated by a single employer, such as a college (e.g. Ann Arbor, MI; and Ithaca, NY), can be expected to score higher than larger, more diverse metros.
The area within a mile of the Madison building has gone from all abandoned buildings to a virtual tech city within the city.
https://www.google.com/maps/place/M@dison+Building,+1555+Bro...
The only negative is that apartment rents have gone sky high, not high by SF standards but high by Michigan standards.