I see this one a lot and it strikes me as lazy thinking.  Sure, we could fit the entire human population on a standard residential lot in West Texas...but we don't.

Humans, of course, occupy and change the most productive areas.  The areas we leave are generally inhospitable to us, or much of anything else.

A good bit of the non ocean surface of this planet is rocks, ice or sand.  The 10% that we are camped on is most of the best, and we harvest off of more than that.