I don't mean to have this come across as snarky, at all, but really the reference for this is the whole of human history.

Wealth is basically self-concentrating. Our political systems tend to end up with a few capital (and often Capitol) cities where the spoils from the plundering, both metaphorical and literal, end up.

The original article does present some interesting and relevant examples of countervailing forces at work as well, and is insightful. But the elephant in the room, as always, is that returns to capital and rent extraction are the primary drivers of wealth, and that the winners tend to keep winning and vice versa.