Let's say (hypothetically) governments find a way to shut down Bitcoin or centralize the whole thing. Even if they succeed, Bitcoin will survive because of its open source nature. Meaning, anyone with the code can just re-launch BTC and restore its decentralized capabilities. Not even purging or banning GitHub (or similar) repositories will be able to destroy Bitcoin. And don't get me started on Quantum computing.
At this point, I'd say Bitcoin is immortal. Wouldn't you agree? If not, may I ask why?
Your input would be greatly appreciated. Thank you.

No, if governments find a way to shut down Bitcoin, then there is no way for Bitcoin to survive with its original form because if they beat such a strong and popular system, then the new copy/paste won't have time to become as popular and adopted as the OG Bitcoin. If it happens what you describe, then we will have a need to create absolutely brand new Bitcoin that will be better than the OG version, that will be more decentralized than OG and much harder to ban then OG.
It's hard to say how immortal Bitcoin is. At the moment, I think it's immortal but after 20 years, 50 years, 100 years? Nobody knows.