I will agree with Armstrong's skepticism on cryptocurrencies. We can even see that Bitcoin is becoming increasingly centralized (by design)
not by design. Capital always consolidates. Or certain structures in society generally for that matter. That's an unsolved problem. Probably unsolvable. Also if we lived in a money-less world, some would have more power and influence than others. At best we could get an ~ 80-20 distribution I guess, that seems to be the rule of thumb of balance in nature.