But over the years to come, people won't rely so much on the centralized banking system, which hits the goal of Satoshi.
I doubt. It's the other way around, which is that, as more years come, almost everything is now centralized.
Bitcoin or any other crypto in general isn't actually used where it is supposed to be. Crypto is mostly treated and used for profit-taking purposes in the future, not to be primarily used because of the decentralized thing or whatever.
This world has been a centralized, government-run world for hundreds of years. That won't change easily just because of the advent of bitcoin, governments will never let that happen and bitcoin won't be strong enough to do that. Governments and banks will still be the rulers of this world until the earth ceases to exist, don't be naive that they will be affected just because of bitcoin.
You are right, we invest in Bitcoin for one purpose only, profit, and once we have enough profit, we will convert it into fiat and other assets. No one uses it for its original purpose, how can we expect it to replace banks one day?