The rate of occupied housing in Detroit has drastically decreased, while average rent has increased. If the supply and demand hypothesis of the real estate market held, one would believe that given the fungibility and non-stratified nature of housing in a given city, cratering occupancy rates would correspond to a decrease in average rent priced. If you believe that housing is indeed stratified and that the surplus of affordable housing has so little an effect on the average price of rent in the entire city, whose average income I should remind you is of under 30 000$ while the average price of rent is of more than 12 000$ a year, then I see no way that building luxury apartments could still mean a sizeable decrease in the price of affordable housing in say, Toronto.