Earlier quoted context omitted.
Capital is used as a synonym of wealth. It's a book about wealth inequality. The book was originally written in French, and land is considered as "capital foncier". Maybe this meaning got lost in translation, but I think "capital" also has the "wealth" meaning in English. Nevertheless, the point I was making still holds. The Medium post isn't a refutation of Piketty's theory.
Yes, that confusion is a decent enough explanation. The important thing I want to highlight, is that as factors of production go, increasing returns to land have different policy implications than increasing return to capital: A general wealth tax might be required if capital was actually the problem; with all the economic inefficiency that implies. I don't know for sure. But increasing returns to land have a simple…
In our current situation, I would worry that taxing only the wealth "stored" in land ownership would create a massive economical crisis as capital tries to escape this new tax.
A broader wealth tax base, with a slightly higher rate for land, is a more prudent approach.