i live in a high COL area and rent is not high because of land costs. there are several empty lots that people want to build on but the discretionary review process for entitlements make it too easy to wreck the permit process (everybody knows this in the entire world; this is the YIMBY line which has truth to it). another factor is the cost per bedroom to build is very high, due to the cost of building in the market (labor, cost of goods, etc). so it's actually everything to do with the building/entitlements and nothing to do with land cost. at least where i live right now. proof: the college cancelled a massive housing project because it was gonna be too expensive per bedroom. this wasn't because of land costs but building costs.

aside, while i'm at it, let's take another swipe at free market and housing: the YIMBY line has truth about regulations preventing building, but if you look at build starts for like the 10 years after the 2008 crisis, you'll see a lack of buildings that happened during that time. they had record housing starts leading up to the crisis, and you know what also existed then? the same regulatory regime that we are now tearing down to help us build what we need. but after the crisis, the builders stopped building because they were fearful about the market. this suggests to me that "regulations prevent building, just let the free market take care of it," is too simplistic and ignores very real data. the market took care of it by not building.