Well, they are buying land because housing exists on land. As discussed elsewhere in the thread, if you make the housing upon that land more elastic (e.g. by loosening zoning restrictions), that elasticity pretty much immediately gets baked into the price of land itself.

This is so significant an effect that there is a highly lucrative business in simply buying low-density zoned land and going through the entitlements to turn it into a high-density zone. This does not just generate a free lunch for a developer to build more units on the same plot of land at the same price, it makes the land instantly more expensive.