Strictly speaking a Ponzi scheme involves a single person or entity doing that, consciously. Bitcoin is… an anarchist self-organising Ponzi scheme? :) It has many of the features of a Ponzi scheme, but largely by accident; there is no _intent_.
The creators of small memecoins often are doing this, deliberately, of course. Some of them are amazingly open about this, often marketing their memecoins as, essentially, “it’s still early” (ie you, the buyer, get to get in before the scheme collapses; like early Madoff customers, you can be one of the lucky ones!).