My parents bought a 2-family in Milwaukee in 1980 for around $30,000. They sold it in 1988 for around $30,000. It's still worth around $30,000, if it's still standing and maintained.

And Milwaukee is not, by a long shot, Detroit— it's still barely below its peak population. Wages have declined, however— an average young person when my parents were young would make the same amount of money as in San Francisco: http://www.theatlantic.com/business/archive/2015/02/for-grea...

(All of these numbers are nominal dollars— the house has significantly declined in real value.)