Nonetheless, despite difficulties, new housing does get built in the city (but yes, likely not at the needed rate). This should still mean there's an improvement over what would happen otherwise.

However, if a person did want to push faster creation of new housing as a solution to housing affordability, preventing price fixing is a definite pre-requisite to that working as a solution.

That sort of puts the lie to the whole idea that it's a meaningfully competitive market then. As new housing is built that existing overpriced housing should have to drop prices or at least not increase as much or else sit empty.

One would hope that the landlords are barred from further collusion resulting in a more competitive rental market in which landlords have to lower prices to be competitive.