Good luck creating a EMP tech that's capable of taking down all the power grid in the whole world with just one button, this is straight out of a Sci-fi movie, it's never going to happen, there is nothing I can compare to been impossible than this, still not satisfied?
The sun, can EMP take down the sun too? Now I don't even run a power grid at home anymore, it's been disconnected because I run on solar panels 24/7, all my electricity with water pump are getting power for the sun.
I still manage to run few Bitcoin home miners too, so what are you trying to say? If the world don't have access to their electricity or network remember that the world is getting advanced, there are cities in China that depends heavily on the sun for energy.
Shutting down the whole Internet seems impossible right now. Not even an EMP strike will do the trick. If the Internet survives, so will Bitcoin. To be prepared for the worst, BTC miners and nodes can be launched in space (on the Moon, or Mars, maybe?) to help guarantee the cryptocurrency's longevity.
In a way, Bitcoin is already immortal. Even if QCs and AI manage to successfully crackdown Bitcoin's network security, that alone won't stop the crypto itself from reviving itself in the future. The code is open source, so anyone can improve it and launch it again. If it abides by consensus rules, it won't be considered a fork. I don't envision BTC disappearing anytime soon. It might live well beyond the last BTC mined by 2140. You and I won't be alive by then, but our descendants will. The future is full of surprises, so anything can happen.