There's no such thing as "payout" in free markets—someone
buys your thing for money (sometimes less money than you paid for it, sometimes more money than you paid for it). So, while it might be a speculative bubble (like Beanie Babies, or Tulips, or whatever), it's certainly
not a Ponzi. Also, the bigger fool theory (which is what you're conflating it with) is also
not a Ponzi.
This might be confusing, because many other crypto products are very Ponzi-like. For example, Voyager literally paid new "stakers/depositors" (a.k.a. investors) with old "stakers'/depositors'" (a.k.a. investors') money to reach the insane return rates they were advertising.