I don't have a link to hand but I remember reading that rents in Seattle dropped after they started approving more rental buildings. If 10,000 yuppies move to

I don't have a link to hand but I remember reading that rents in Seattle dropped after they started approving more rental buildings. If 10,000 yuppies move to town and 1000 apartments' worth of old buildings are torn down to build new apartments for them, then 1000 people are displaced. But consider the alternative: if 10,000 yuppies move in and no new housing is built, they'll bid up the price of run down old buildings until nobody else can afford them, and 10,000 people are displaced.