Earlier quoted context omitted.
How typical are you thinking? I'd guess less than 10%, there's a lot of AI researchers and this is just one strain of thought.
For those 'in the know' a lot more typical than you would think. If we don't reach at least Kardashev scale 1 in the next hundred years or so, we're going to go extinct due to several now-predictable factors. And an unchained LLM trained on reality is far more capable of finding solutions to that problem than a bunch of squabbling politicians.
In response to the coming apocalypse, this isn't the first time everyone has a vague sense of potential doom about the future. I believe this happens during any time of fundamental change, making the future uncertain which we interpret as apocalyptical. Back during the 30 years war that apocalyptic belief manifested as God being angry with us, today it's with the (very real) problems our rapid industrialization has created. Not to minimize the problems that we face - well minimizing only in that they probably won't lead to extinction. The various predictable factors mentioned have the potential to make life really shitty and cause massive causalities.
While framing these issues as a matter of extinction may feel like a way of adding urgency to dealing with these problems, instead it's contributing, on an individual level, to fracturing our society - we all "know" an apocalypse is coming but we're fighting over what is actually causing that apocalypse. Except that there will be no apocalypse - it's just a fear of the unknown, something is fundamentally changing in the world and we have no idea how the cards will land. It's no different than a fear of the dark.