Everyone is entitled to their own opinion but Im not sure how you can call Bitcoin a Ponzi scheme!
"Ponzi schemes rely on a constant flow of new investments to continue to provide returns to older investors. When this flow runs out, the scheme falls apart"
In this case the returns are in the form of a higher price on Bitcoin
(
https://en.wikipedia.org/wiki/Ponzi_scheme )
So you fundamentally misunderstand the bitcoin network.
By your definition of a ponzi, if somebody sells me Apple stock that they purchased for a lower price, then they are participating in a ponzi scheme.
The bitcoin network is transparent. There are no paper profits.
Madoff falsified account documents to create fictitious profits. When someone wanted some or all of their money, he raided the account of other investors to make the payout. This is how a ponzi scheme works.