It is possible that this average is being brought down by the liquidation of foreclosure homes which are of below average quality.
It would be more interesting to see the price history on homes currently being sold in middle class neighbourhoods.
Doing a search for 3BR, 3bath, newer than 10 yr old homes, 2000+ sqft in Dearborn comes up with the following typical listing:
http://www.realtor.com/realestateand...9874?source=hp