What makes a Ponzi scheme, a scheme is; a guaranteed profit. Crypto profit is not guaranteed at any time, the criteria is not met thus is not a Ponzi scheme.
It's really simple. Take for example, Bitcoin:
When Bitcoin reaches its next all time high, literally everyone is in (unrealised) profit. However, to get that 'profit' they have to sell it; mostly starts with the few rich speculators at the top of the pyramid accumulating starting to sell and a new fool who buys in late.
The next time Bitcoin crashes, the ones at the bottom who bought in late and hold it always lose.
Therefore the criteria is met and it is a Ponzi scheme and that is what Bitcoin is really useful for.
Maybe it’s a super ponzi because unlike BTC, Amazon can keep issuing common stock, which pays no dividend. BTC is capped at 21M.
Non-dividend stock is shuffling funny tokens between investors who hope it will be worth more in the future.
So either lots of things are ponzis or maybe they are not ponzis at all, and the definition doesn’t work.
I am not convinced that cryptocurrency qualifies as a Ponzi scheme (the real distinction is that the person at the top knows they’re selling a fraud) but it’s certainly driven by pure speculation.