Also, this isn't exactly a revelation for those who are in businesses that hinge on physical location (retail, restaurants, etc...). Landlords provide little of value, in most cases did nothing to earn their money (around here the landlords in downtown business districts are the descendants of those who owned that property 100+ years ago) and merely act as parasites.
In the case of those who own residential properties, they merely bought at the right time, and due to the scarcity of land are earning far more than whatever value they're providing.