Those are answers that don't factor in immigration at all. And are still deceptively complicated.

Housing is an investment, just as much as the foundry that makes the front doorknob. Both are critical to our standard of living, but both also cost a lot of money to put in place. Somebody will have to pay to build more. That could be the government, like you're saying, or it could be developers who are looking to cache in on the high prices and therefor bring them down. Which one should do it is complicated.

Not intractable, though.