> Even if it's true that a few large businesses own most rentals, that kind of oligopolistic behavior should be undercut by new people entering the market by bu

> Even if it's true that a few large businesses own most rentals, that kind of oligopolistic behavior should be undercut by new people entering the market by building more apartments - unless there's a big barrier to entry, like the difficulty in building things when there's restrictive zoning! You're missing the forest for the trees here. The 'new people' entering the market sell the apartments and buildings they create to the big businesses in question. I've lived in apartments for my entire life, eventually they all get acquired by Greystar. Even the smaller ones.