If house prices were directly connected to inflation, there would be no issue.

But they run far above inflation. This is what gets a pack of landlords involved.

There's a point where putting your money into a basic stock market tracker gives a better return than landlording. That's when they go and do that instead. It's a lot less up front investment, and a lot less risk.

It's mostly the spiralling house prices that attracts the landlord class, not the rent. The house is making money even if there's nobody in it. Rent is just the icing on the cake. Right now they just cannot lose.