Shrinking populations should make housing very affordable

somehow, it doesn't work that way. For example, Latvia lost 30% of its population but housing didn't get cheaper.

yup, and we just lost 10,000 homes in California. We will be losing housing every year. Where I live they just build mansions.

We don't want to wait until we're in freefall to correct the decline.

There will never be a free fall. You guys are watching too many dystopic movies.

We don't know if there will be a free fall, that's the most central tenet of this issue. You are living in wishful thinking, it's uncharted territory, there is no "knowns" to base your statement on.

Even if one tries to apply first principles it's not something that can be derived easily to hold your statement as fact.

I wonder if people on Easter Island were telling each other this.