There are multiple ways to crash the value of housing.

One of the easiest would be a 100% capital gains tax on property values (not building value). You can no longer profit from simply holding onto land. You can develop it and earn a profit from the building work you do, but just holding it and doing nothing no longer generates any value. This profit motive is what's pushing the investment in property that drives up prices, and removing it would crash the value of land overnight.

Or, and this is my preferred option, a monthly land value tax (again not on buildings) that is set high enough to replace all of the income taxes, then drop income taxes to 0%. This way we tax people based on how much land they use (which includes how desirable that land is just based on the assessments) not based on how much work they accomplish. People who live in smaller amounts of land (like a condo) pay less tax, and people who want giant mansions near cities can pay the rest of us a bucket load of money that the rest of us workers now save on taxes. Instead of replacing income taxes, I also wouldn't mind seeing a similar universal basic income system.