Satoshi didn't find bitcoin for making people rich,he just want decentralized payment system
Exactly. The main purpose of Bitcoin is to "decentralized payment system".
which can save us from inflation which literally means our money will not lose value due to inflation.
Indeed, we avoid inflation from conventional currencies. But in crypto, we are threatened by very high fluctuations. So, this does not guarantee we not lose value at all, because both types of currencies equally have the same risk.