Besides this, Satoshi seems to have had quite a few reasons to develop
Bitcoin such as fleeing from banks, creating a trustless system, etc.
OK. So my reason is to protect your life savings from this ponzi scheme called bitcoin

I want to prove that decentralized trustless system can not exists in long term.
It either transforms to centralized system or loses its security.
In the one million instances where someone has lazily called Bitcoin a ponzi scheme, I have yet to see anyone provide the answer to this obvious, but heretofore unasked, question:
If Bitcoin is a ponzi scheme, who is Bitcoin's Bernie Madoff? If there is no Madoff (or more respectfully, no Ponzi), there is no ponzi scheme.
Investors (speculators) in Bitcoin are not relinquishing their capital to anyone for nothing in immediate return, with the expectation of nothing more than a high-interest yield on that capital. They are buying a commodity/tool/currency. They may have an expectation of return/profit/yield/revolution/utility that will not materialize to their satisfaction, but they also holding something in their hand while they're waiting. They have not turned control of their capital over to a central actor - Madoff, or Ponzi, or whatever imaginary unnamed actor the "ponzi scheme" gossips are inadvertently invoking.
Bitcoin may be something imperfect doomed to failure, even doomed to manipulation, but it is not a ponzi scheme.
One by one - everyone should stop malleating the vocabulary of the criminal financial world.