The funny thing is, I completely agree to everything you just said, yet, I don't see any contradiction to what I was saying.

The only aspect of Bitcoin that makes it _a bit_ like a Ponzi is the financial incentive to attract more people after you are in.
You don't have that with religion. You don't have that with belief. You don't have that with idea. If you have a great idea, your financial incentive is to keep it secret until you implement that idea as a startup. If you have bitcoins, your financial incentive is to attract more Bitcoin users. If you bought into a Ponzi, your financial incentive is, usually, to attract more victims.

The aspect that makes them different is that Ponzi is a negative-sum game, whereas Bitcoin is a positive-sum game.
When you get involved in a Ponzi, society as a whole loses. Those who bought in last, lose the most.
With Bitcoin, society as a whole wins. Those who bought in last, profit the least, but they still profit, in the long run.