The development of technologies always follows a well-known curve of their adoption, which includes a period of exponential growth. And Bitcoin is no exception. The fundamental difference is that Ponzi and pyramid schemes create value only for the oldest investors by simply redistributing money from new participants. No economic component. Just plain theft.
Bitcoin also creates value for both earlier investors and new ones, providing more and more opportunities to use the currency, the amount of which, moreover, is limited. It is not a deception or theft, but simply the good old law of supply-demand in action, or in other words, the ancient economic principle, in the service of the modern monetary system.