Perhaps by checking what a Ponzi scheme actually is and seeing whether bitcoin matches the criteria?
In my humble opinion its current price is
partly based on a pyramid schmeme...but that is the property of every bubble
Rather like the USD government debt then , which depends either on selling more debt to new investors to pay off its existing investors or on creating more tokens to do the same. Point the finger of Ponzi or pyramid where it really belongs, central banks and managed fiat currency.