So is the largest contributor to the problem just lack of land? Seems like most of the other problems from the article can be solved with money, but a lack of land makes it hard to build anything

I once calculated that if we reduce the land use for livestock by 50% and then use 10% of the newly freed land to build housing (the other 40% can become nature), we can build a city something like 1.5x times the size of Amsterdam, the largest city in the Netherlands.

It’s not a lack of land. It’s how the land is being used. Almost half is for livestock (or more accurate: to dump the shit of that livestock, as the majority of the animals is kept indoors).

Is the land the livestock are currently capable of supporting dense housing and is it close to urban cores. Or would you just build sky scrapers in the middle of nowhere, because China tried that and it failed.