The two real problems that prevent solving the high cost of housing are people who don't want housing of a particular type (housing for poor people or housing for rich people) in a particular place and authorities that defer to them. These are people problems, not logistics problems. Everything else is pretty easily solvable if we can resolve one or both of those.
Those aren't easy to solve tho. So whenever I see a post with "it's easy" to solve the housing crisis, I think, "Have you met people?" If convincing people of the obvious right thing was easy, quite a few problems would be solved.