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.

Quantum computers are a real threat and that's why cryptographers already work to combat it, if Bitcoin will not hardfork to combat it as well, it's doomed.
As for re-launching a PoW cryptocurrency, today it's close to impossible to start a legit (no premine, no dev-tax, etc.) project on PoW because it gets attacked pretty quickly, project like this would need to have a very high hashrate from the very beginning, decentralized and ready to combat attacks.
Back in the days when cryptocurrency space was only known to true enthusiasts it was not a problem but today it's a whole different world and you can see plenty of example where a project was destroyed because it had not enough hashrate to secure the network against 51% attacks.
You think investors would put money into re-launch of Bitcoin ? it would be another worthless project and no one would want it because there are better projects out there.
The only thing Bitcoin has going on for it, is it's age - being the first cryptocurrency, the
original "Satoshi".
BTC may seem immortal. But it would die in a minute in a worldwide EMP collapse.
Such strong EMP would also kill all living creatures, you can as well say Bitcoin would die from atomic bombs.
As you said, its open source nature can be updated by anyone and its coding can be adapted to the most advanced technology. But it is not known when it will happen, maybe 50-100 years in the future with a more advanced version of the technology. That is personally why it is not right to say bitcoin is eternal, but rather can be updated but still maintain the essence of bitcoin. This is just based on my assumption so it must not always be the same as others.
More advanced technology is already here and updated "Bitcoin" is here too, it's called
Monero.
Technology advancement happens faster each year and we're only at the beginning of it, we barely put our foot out of the cave.
Bitcoin itself, the network is indeed invincible just like gold is. However that doesnt mean the govs are completely helpless against it. They dont have the power to shut bitcoin down but they can punish those who use bitcoin because they know everything about us.
The US government seized their citizens gold and punished those who didnt comply. They did it before and they can do something similar again.
What good is it if I am in prison but bitcoin is still operating?
We need to do something about this one instead of worrying about bitcoin.
That's why privacy matters, without it government will force you to give up your Bitcoin or will blacklist them and put you in jail if they move plus some big fines.
The true freedom is when government does not know how much you have, unfortunately it's not possible with Bitcoin.
/Over&Out