> We know what the root problem is, housing supply.
How do we know that is the root problem?
If we knew the root problem is housing supply, and we haven't been able to address housing supply, then clearly housing supply isn't the root problem and it's something like entrenched interests (NIMBY's) or alignment problems regarding people not wanting to be taxed. Clearly there is some more "5 why's" work to be done.
I think it's hubris to think you have the answer for a problem that's been around for 3 decades+ worth of administrations.
> We know how to make cities far better and reduce total cost of living in them.
This also needs citation. I don't think we do. It's not "build better public transportation" or "build more housing", it's build more under the American legal system, under American culture and American politics.
These problems require systemic thinking. Why is the website down? Because we don't have enough web servers (not enough housing?)? No, because the databases are overloaded slowing down requests, because we haven't increased the number of database shards, because the database team is understaffed, because our hiring pipeline has problems, because recruiting is understaffed... etc.
We know what the root problem is, housing supply. We know how to make cities far better and reduce total cost of living in them.
There would still be many homeless left, but at that point you might actually have a hope of actually dealing with that specific problem.