Cryptocurrencies cannot prevent accumulation of extreme wealth in the hands of a few. The reason is simple, yet important: Money is not wealth. Money represents wealth. If you restrict the amount of money per person, wealth will be represented by a different metric – camels, for example.

> Yes that's a big 'if', just like for any other idea.

No. Any idea that requires such an "if" (i.e., the implementation has to be perfect for the idea to succeed) is doomed to fail.