> Sometimes, you cannot build more housing, or denser housing ... If you turned San Francisco into Manhattan, and still had unquenched demand for housing while

> Sometimes, you cannot build more housing, or denser housing ... If you turned San Francisco into Manhattan, and still had unquenched demand for housing while still maximizing every square meter of three dimensional space within desired geo bounds, what then? Using Manhattan as your example of maximum possible density is... odd. Kowloon City [1] had much higher density and had the disadvantage of poverty. I'm not saying that we should turn all residential areas into facsimiles of Kowloon City, but there is a ton of space between what currently exists - even in Manhattan - and that. I'm deeply skeptical that any place in the US or Europe has reached the limits of building more housing and is forced to look at other options. ___ 1. https://en.wikipedia.org/wiki/Kowloon_Walled_City https://en.wikipedia.org/wiki/Kowloon_Walled_City