> Notice concepts such as PoS would make it even more concentrated.

That is a common misconception, it seems to me. Assume a PoS scheme in which the probability that you get the reward is proportional to your share of all coins. Yes, large holders are more likely to get the reward, but if they get the reward, it basically increases their share by close to nothing. If a small holder gets the reward, they get a substantial boost. It averages out.

It is a bit like a savings account. Everyone gets X% interest a year, so the big holders get more interest than the small holders, sure. But the proportions of wealth stay constant.