It's also just not true in a lot of areas. I live in an area where nearly every house is already an apartment building or a 100-year old mansion converted to co

It's also just not true in a lot of areas. I live in an area where nearly every house is already an apartment building or a 100-year old mansion converted to condos or apartments. New construction is all multi-family and transit-oriented. Prices are still high because there's just too many damn people trying to live here. The problem is not that there isn't enough housing in any one particular area. There are a lot of issues with the argument that everyone everywhere just needs to build as much as possible, no matter what, and it's disingenuous to any such argument as NIMBYism. The problem is that there aren't enough nice places that are actually comfortable to live: good access to transit, access to green spaces, not too much traffic, access to shopping and grocery stores, etc. This is broadly because of how American cities and towns are designed.