>...the 'taxing progressively higher any property a person directly/indirectly owns after first N properties' are seriously very much needed...

I don't see it in the article, but the progressive nature of the tax is important. It makes it harder for large landowners to pass along the tax, since they must compete with smaller landlords. The net effect should also stabilize land appreciation, which will no longer rise with rapidly increasing wealth disparity as it has in the past couple of decades. And we won't need clunky, patchwork solutions like the ban on home ownership by private equity.