alt Hacker Newsreal estate must be the worst thing to use as an argument for "it's a free market" - because its one of the types of things which every stock is it's own, truly unique monopoly. I can't "freely" produce the same commercial property, unless I already own that property.
Commercial property is only unique in number on a street location factor.
Plenty of the same type of commercial properties exist right next to each other, happily too.