[epistasis]

20 years of under building from the last housing crisis.

But more importantly, the most economically vibrant areas, with the most ability to provide economic opportunity, have been stunted by lack of housing: NYC, SF Bay Area, Boston, San Diego, etc. This transfers wealth to current landowners in those regions, but let's only the highest income job professions move in, and overall slows the ability of those with less to access economic opportunity.

And those areas down zones half a century ago, capping out their housing ages ago. That's the true lack of housing, and it's all locational. The only thing you can't build more of is land, and it's not fungible. Best we can do is build up in those special areas where there's the magic combination of people to allow for more productivity and more jobs. (Which also happens to be far more ecologically friendly too, but I'm aware not everybody cares about the environment these days).

[mplanchard]

Yeah I ran some numbers in another comment on this post, and I was a bit surprised to see that NYC’s units per capita number is about 42%, 5% fewer than my much smaller (but also plagued by lack of housing and lack of affordability) city at 47%. They’re planning to add 200k units over the next ten years, which is a start, but even if we assume no population growth, that still only gets them an additional 2.3% more units per capita. They’re also trying to spur more private development.