This is such a naive take I am astonished it's a very common answer in the threads. OK like there is software you can download right now form the dark web, hack loads of laptops and copy any code you like there. It's so trivial that you cannot shutdown a system that it boggles me. Even Marc Andersen claimed that although you can easily see he has alterior motives invested billions in the tech.
It's like a movie scene where top scientists from AI labs are working to solve the alignment problem and Jeff Bridges knocks on the door and says "hey guys, have you thought about unplugging the damn thing"?
You are assuming a centralized super intelligence is better than multiple separate intelligences. Maybe controlling hardware (bodies) is very hard to do in a centralized fashion. Maybe the delay in transmitting commands is too high to allow for a centralized processing unit to handle it and that's why animals have evolved as many separate individuals.
Humans and other animals have evolved during millions of years of evolution. We might be very efficient collectively. A single centralized intelligence might not be very efficient or even possible. We might just kick its ass and take leaps around it. We don't know. Claiming every new step in our discovery might bring the end of humanity it's like when they built the Eiffel tower and all the farmers around were scared it would collapse and kill everyone.
THE WOLF, THE WOLF, THE AI WOLF! https://en.wikipedia.org/wiki/The_Boy_Who_Cried_Wolf