Crypto(currency) a Ponzi scheme? Evidently. But could it be even worse? Yes, stablecoins are designed to make Ponzi-like theft irreversible, by parking actual cash at the winner in this scheme: the owners of exchanges. Read more (archive). Owners which, according to a recent study, is a small group of people (archive).
Interesting: someone wrote a paper on how this is basically what happened to the Bank of Amsterdam 1609-1820, click. Still have to read this.