I assume Detroit has a lot of the same problems that St Louis has, they are both great little cities with an up and coming tech industry but hiring skilled talent and conniving them to move to the area is a nightmare.
Oakland county to the north of Detroit and Washtenaw county to the west of Detroit are two of the wealthiest, most highly educated counties in the country.
And the cities surrounding Detroit have a lot less problems than the city itself.
I think the parent's point still probably stands. Wherever they end up, assuming there really is a 50K HQ2 in the end, they have to convince a lot of people to relocate. And a lot of people would be: 1.) Detroit, no thanks or 2.) I can live with Detroit but when I end up leaving Amazon after 2 years like so many people do, I'd have to find a job in a different location. I imagine the talent question at least factored in--schools in the general area notwithstanding.
"My point is that the problem is largely one of perception."
That very well might be true, but that's Detroit's problem to fix, not Amazon's. Amazon doesn't want to have to deal with that; they want a place that they can get people to come to day 1.
Detroit is shifting fast in this regard. It still has problems, but it's not the city it was 10 years ago, which is what I think a lot of the perception still is.
The Detroit bid put together by Dan Gilbert and team highlighted the fact that almost 50 million people live within a 5 hour drive of the city, with a huge collection of major research universities. Another big push or two like Amazon HQ2 can provide, and I think the city and metro area become highly attractive as an economic destination like Chicago dominates today in the same region.
And the cities surrounding Detroit have a lot less problems than the city itself.