You can't extract more rent if you charge maximum of what your customer can afford. If landlords raised rents collectively then people would simply sprawl out t

You can't extract more rent if you charge maximum of what your customer can afford. If landlords raised rents collectively then people would simply sprawl out to suburbs. City rent is an aggregate monopoly - there is not enough supply of housing to have effect on downward pressure for rents. Demand is overwhelming supply. Landlords' rent prices are not driven by competition but determined by what the market can bear.