> We don't tax ownership of tv's & shoes, so it makes sense to exclude floorspace as well.

give it time and that will be taxed too. in more states than not in the US citizens are not only not allowed to own houses but also cars without paying the government a fee every year - the shoes and tvs and kids toys are coming :)

In most places, registered cars are taxed but unregistered cars are not, so classic/museum or inoperative cars can be owned without paying the government a fee every year. (This makes sense/feels fair to me. Registered cars are expected to be used and the use of cars costs the government significant money and has externalities on the public. Unregistered cars mostly do neither of those things at least no more than a bunch of shoes.)