Does the fact that bitcoins are limited prove that the system is a scam?
You make a lot of interesting claims. The ethos behind bitcoin is similar to that of gold, hence 'mining'. Gold is also limited supply and I am certain that people who first found gold a long time ago are rich beyond their wildest dreams. That does not stop anybody trading gold for something of value.


  ... a kind of ponzi scheme ...


Ponzi scheme is a particular arrangement which Bitcoin certainly is not.