As for purchasing land as a commodity, how would you prevent trespassers from attempting to utilize your land and homestead it in violation of your property ownership? You'd have to expend resources to secure it, which is in effect the upkeep of that land. Maintaining large tracts of land absent a socialized enforcement agency like government is costly (though cheaper than the funds used to that purpose currently) and it would have to be paid by the individual attempting to maintain that land as a commodity. Excluding people from unused land just to hoard it is a financially losing proposition except in the very long term, and one would have to be unimaginably wealth in order to maintain that claim over time.