The author is wrong about Detroit's revival. One Detroit is reviving, while another is not. This isn't just Detroit, this is America. I was cruising past food lines in SF this morning. Few non-brand businesses can afford the rent, resulting in a posh desert, but people are waiting in line for food outside.
I didn't even get the impression that it's reviving. What I read was that the community, mostly abandoned by the government that's supposed to take care of it, is surviving - not thriving - on its own. They took necessary measures - advanced measures, grant you, but nothing other communities couldn't implement - to protect their living. Which isn't to say that I don't admire the effort or the implementation. It doesn't feel like revival to me. What do you mean when you say "one Detroit"?
Housing is getting quite expensive in some neighborhoods and the city center. Many new businesses and restaurants have been opening, and living spaces are being built and renovated. One Detroit is quickly gentrifying. But, Detroit is a very big city. Much of Detroit is not feeling this.