Any claims that bitcoin is a Ponzi Scheme is laughable. Anything that could be classed as a Ponzi has been carefully orchestrated as a fraud. If that's your claim, please point out the individual or individuals who have masterminded this fraud? Secondly, point me towards a Ponzi which has been run through multiple peaks and troughs. You won't be able to as there's no such example.
You're one of the few holdouts in terms of attempts to claim that bitcoin equals Tulipmania. They're in no way comparable given that tulips possess none of the internationally accepted characteristics of a store of value or money whereas bitcoin on the other hand does.
Whilst you can't be objective enough to accept the possibility that bitcoin will continue to be successful, I'm on record as accepting that it could potentially fail. However, in the case of pensions or anything else for that matter, I've long since advocated for the inclusion of no more than a few percent within an overall portfolio. To my mind, it's now irresponsible to not gain that limited exposure to an asset that presents with asymmetric risk.
Here's a popular culture take on the type of practice you're trying to shine a light on, though.