Also, if you wanted to build higher buildings to accommodate more people in the same space, good luck doing that in a city center, because there's no space for such thing.
I have seen a three story building knocked down in Hong Kong and a 20 story building rise in its place without any damage to the structural integrity of its neighbours. Engineers are really good at building things if they’re allowed to do so, even under significant constraints.
If there is a run down and empty building, then sure, but you won't find many.
Housing cannot simultaneously be affordable to everyone and a good investment. Society needs to pick one and write laws accordingly.
Furthermore, I'm not completely convinced that restricting rental property ownership to property management companies who can afford to build apartment complexes is inherently more equitable than letting a middle class person with good credit buy an extra house and rent it out. Where I'm from originally (Alberta), it was common for electricians/plumbers/tradesmen to buy an extra property with a combination of credit and wages and maintain it. It's a relatively simple and time-tested path for moving from working/lower middle class to being upper middle class or even wealthy.
(And it's possible they are already at that level, or near enough. It is after all the price point that a seller always tries to hit...)
At 7.2%, the doubling period is about ten years.
This should cool down the market.