I'm not convinced that cryptocurrency is a ponzi scheme.
Crypto is an asset, not a market. Decentralized digital assets cannot inherently be ponzi schemes. The level of transparency and trust in the market on which they trade is what determines if it's a ponzi scheme. I am convinced that many cryptocurrency markets/exchanges are ponzi schemes and need to be significantly regulated so that market manipulation is reduced significantly, especially when non-accredited investors are involved. However the fact that these markets trade crypto is not relevant.
Every time crypto implodes (what are we, on the sixth extinction?) people love to stand by the sidelines and say "see I told you so!". All that's really happening, as someone else on HN aptly put it, is we're speed-running the history of finance out again in crypto-land. It is a shame that self-regulatory efforts that Gemini and Circle tried essentially failed, but it's not really surprising. Power corrupts, and there's almost no regulation in the industry. The industry has clearly shown it needs regulation, so the time to claim that it doesn't is completely gone.
I for one, am extremely optimistic about what cryptocurrency means for the human race. I honestly believe it will do for the human economy what the internet has done for knowledge. I hope I am not wrong, and I'm certain that there will be dark periods full of bad actors, just as there was/is for the evolution of the internet.
I should state that I own no cryptocurrency at the moment, even while being optimistic about the future of cryptocurrency.