So a ponzi relies on new rubes to come in and pay the rubes on the layer above them and then bring in more rubes so they can get paid? Right?

Lemme skim the Ponzi wiki - https://en.wikipedia.org/wiki/Ponzi_scheme
(Why there is no bitconnect direct link on this page is weird - https://en.wikipedia.org/wiki/Bitconnect )

How does that work with bitcoin? Or ethereum? Or any other top 100 market cap crypto? How do the new rubes pay the old rubes on the blockchain or on layer 2 or via another blockchain? Via affiliate links? Some kind of side channel or fiat off ramp to pay people? How would that work?

I've mined it via GPUs and power - BTC, ETH, RVN and XMR.
I've earned it via bounties and making art for NFTs.
I've staked it on DEX - decentralized exchange(s)/CEX - centralized exchange(s).
I've used lending platforms.
I have no upline (except the IRS) and no downline (except CEX fees and tx fees).

A lot of people see crypto and especially bitcoin as a ponzi but I don't see it in the space generally - but there are exceptions of course. There are DEFINITELY some chains that are ponzis - https://coinmarketcap.com/alexandria/article/5-of-the-biggest-crypto-ponzi-schemes

Doesn't mean they all are. But anything that touches money can be subject to scams. No doubt about that.