AI future scenario by Joshua Clymer

Joshua Clymer's "How Takeover might happen in 2 Years"
https://www.lesswrong.com/posts/KFJ2LFogYqzfGB3uX/how-ai-takeover-might-happen-in-2-years
Audio version if you prefer (AI narration, do beware):
https://youtu.be/Z3vUhEW0w_I?si=KYEbW1_7agMlge6C

A scifi-esque scenario, starting at the current state of AI development, progressing into hyper-exponential growth, and an unhappy conclusion beyond.

As the author states, not a prediction, but rather an imagined "worst nightmare" case.

Are we on a trajectory where such scenarios are of a concern? Or is AI Doomerism all basically nonsense?