I'm not pro-AI by any stretch for a huge number of reasons, but in my day job as a technical product manager I have to use a number of AI-powered tools and workflows. Whereas 18 months ago they were a novelty that the bosses were enamored of, today they get real work done and speed up a number of key areas, mainly like fancy automation workflows (which have been around forever). The rate of improvement and capability for certain use cases has been very, very rapid. We do seem to be reaching a plateau though. The tools and models from 6 months ago are just about as good as the ones from today. And China's models from today are better than the US's models from 6 months ago, but at a fraction of the cost.
So when I hear people talking about the "end of the world", I think a realistic case for that is that the AI tools that come out in the next few years will be good enough to do a fair amount of white-collar work, and we won't have a plan in place to deal with all of the now out-of-work people that leads to. Whole classes of jobs in areas like data entry, telemarketing, and customer support will be almost entirely automated out of existence. New classes of jobs will be created, of course, but it's hard to imagine them existing in sufficient numbers to make up for the losses. And this is just for LLM-workloads.
In other areas, other types of AI are already enabling robotic automation of factories and in the near-ish future might make self-driving truck fleets practical. This would be devastating because factory workers and truck drivers make up like 30% of the US workforce -- and again, there are no signs of new classes of jobs that could absorb the out-of-work workers, and no plans for a social safety net or wealth distribution.
So I'm not worried about a rogue AI unleashing some bioweapon or launching a nuclear attack. I'm worried about a bunch of CEOs deploying barely-acceptable AI to displace millions of workers as soon as it is safe(ish) to do so.