Yes, Detroit will host the Olympics, but it will take time. The city needs a lot of financial help, but once it turns itself around, the Olympic committee would be foolish not to let them host. It will be a rags to riches story in a way, and we should all root for the city of Detroit.
Given the cost of hosting the Olympics, it's unlikely that many US cities will ever host the Olympics. Considering the economic state of Detroit, it's difficult the people there would approve of the spending that would be required. Until the cost to host the Olympics goes down, which is unlikely given the substantially increased cost of hosting, it would be highly unlikely for Detroit to ever host the Olympics.
It is very difficult to make a successful Olympic bid and one of the major factors is the overall image of the city. The organisers tend to favour historic and highly populous cities like Rio and London for this reason. Unfortunately, Detroit does not have this factor in its favour and nor is it likely that the Olympic Committee will trust the city with the financial aspect given their recent troubles and the problems raised by the budget in Rio this summer.
No, I do not think that Detroit will ever host the Olympics. For the most part, I believe this because of Detroits economic state in today's economy. Detroit went through some rough times and the majority of the population has moved away from Detroit because of the economic turmoil. I do not think that Detroit has enough money or people to build all of the buildings and get the city ready for weeks of Olympics.