Build housing. Build too much of it, to the point where it’s hard to sell and you have to lower the price to find buyers. That’s it. Housing is a supply problem. The housing crisis isn’t happening because houses cost $2,000,000, it’s happening because there are a dozen buyers ready to pay that amount for it.
The only nit I have (and I think this is actually what you meant) is we must build more housing. I say this because often people think it's good to tear down an old house and build a new one. That isn't helping things (and I'd argue actively hurts things).
Why would someone build too much housing that makes it hard to sell? Government incentives? (I agree with the want, I don't know how the free market would do it on its own without incentive, when there's already lots of incentive to have not-enough-housing.)
Yes, it will all collapse someday, maybe soon. But as long as housing is treated as an investment, it can remain unaffordable in the face of supply surplus.