In a way, it doesn't matter who controls what and who manipulates what. There is one aspect of Bitcoin that makes it a bit like a Ponzi. Once you are in (but not before that), you have a financial incentive to attract as many new users as possible, to drive the price up. Aliens? Fine, I'll help them spread the word. Some rich guy? Fine, I'll help him spread the word.
Let me stop you right there. I know you said "a bit like", but still, tired of hearing this for third year straight. People should already drop that term. No, bitcoin is not a "ponzi". By your (lack of) definition, any religion, practice, idea, or belief would be a ponzi as well.
An important part of a ponzi scheme definition is that it should attract money at an increasing rate or it collapses, because it can not generate any legitimate profits itself.
Bitcoin is completely different. First, even when new money are completely gone, nothing happens - conversion rate adjusts of course since there's less demand, but bitcoin does not lose any of it's properties, see second half of 2011. And second, bitcoin generates quite a lot of profit even in a closed eco-system when serving it's purpose - as a common exchange medium for any digital (or even real) goods.
So no, even though short-term speculators are interested in driving the exchange price up, you are mistaking wishes of a small subforum population for bitcoin property. It is not. Speculation subforum may be a ponzi - there are in fact hundreds of HYIPs (ponzies) running on top of bitcoin - but it is nothing but a tiny dot on the side of the world-wide phenomenon that is BTC.