It's an interesting idea. So much of the US is just uninhabited land. I could see such policies not leading to overcrowding, but rather to increased development and economic growth across the country, particularly if combined with something like the Homestead Act.
His other shtick though is "popularism" which is just that politicians should focusing on doing things that are broadly popular. It is (on my reading at least) not so much that this is "desirable" in a normative sense, but just that it is the only way to actually make progress.