> Detroit is mostly reviving because Ann Arbor, where U of M is, is way too expensive.

I wouldn't say "mostly." It's mostly due to huge numbers of job moving to or being created downtown by Dan Gilbert's umbrella of companies(mostly Quicken Loans). Additionally, many businesses in metro detroit are moving from the suburbs to downtown.

I'm not so sure Detroit is any cheaper than Ann Arbor these days, either. At least not in the downtown & midtown areas.