> If the housing was truly affordable then why is home ownership so low?

If rent is dirt cheap, and tenant protections are large, most people prefer to pay little rent, and invest their money in stocks or some other asset, than put all of their money into a single asset with very questionable performance and high risk (a house).

You can have financial independent, fully passive income from stocks, and just pay a little bit of rent with it. Or you could have a house, be tied to a 60 year credit plan, and have to work until you are 70 years old.