Increased rental supply at the cost of decreased home ownership.
There is already price manipulation with rental properties. If a cartel is in control of enough of the supply they can set their prices as high as the market can afford. There is already a nationwide shortage of affordable housing in desirable places with jobs and the idea ITT is that it will only get worse as the investment class are the only people that can afford desirable property.
> they can set their prices as high as the market can afford.
which is the correct price - because you dont need a cartel to set the price at as high as the market can afford; each individual landlord chooses to price their rental at the highest profit they can, with the lowest chance of a vacancy.
A cartel makes it possible to set the price _higher_ than the market can afford. Which is why a cartel is illegal.