I don't see any lack of incentive outside of poor infrastructure but hey, it doesn't seem to stop LA.
The M-1 rail is a joke. It goes from New Center to downtown, which is like a 4 mile stretch. It's the People Mover 2.0, public transportation lip service. It doesn't connect the burbs to the city, which is what we need. Not a personal shuttle for Quicken Loans employees living in midtown.
Our problem is that the northern suburbs get to vote on public transportation and they always vote against it. People who live in the burbs closer to Detroit (Ferndale, Royal Oak, Oak Park, Hazel Park, Roseville, etc) want to be able to ride something into the city so they don't have to deal with traffic and parking.
I can't say I care very much one way or another wether Amazon comes here, I just disagree with the sentiment that Detroit is unworthy of it.