People love to say that but they own a very small percentage of housing in reality. What’s driving housing costs is also supply and demand. Especially supply, since we’re not allowed to build any houses in most places people want to live.
They are responding to the market. If they overbuy then they will lose money and have to sell at a loss, at which point you could snap up some good deals.
The funds themselves say in their financials that they view housing as profitable because of the various restrictions on supply in every desirable city. They explicitly say that if those restrictions were lifted they would not be able to make money in that business and they would exit.
Or to convert them into apartment buildings