Kind of taking this a step further, what is the worst thing that an AI run amok could do to existentially threaten the human race? I feel like almost anything could be short-circuited by some form of "pulling the plug" before it got too far. But, hypothetically, if it were possible to launch nukes without human intervention, or with maybe a small amount that could be socially engineered, that seems plausible (or releasing some kind of super-pathogen that is stored in a lab somewhere).
So, what if, along the lines of MAD doctrine and the plot of Battlestar Galactica, the best thing we could do for AI safety is just to engineer our other systems so that a hypothetical superhuman adversary could not use them against us? Which is just making our world safer all around rather than trying to kludge arbitrary limitations into an "intelligent" system.
(This doesn't really solve AI child porn and fake news but those things are mostly just imaginative reflections of the people using them and you can't really fix that any more than you can stop people from doing it themselves)
Probably convincing humans that untrue things are true. Think less "AI launches nukes" and more "AI convinces people in country A that country B is trying to subvert & destroy them, while it does the same for country B wrt A."
I strongly disagree with the opinion that it has been a net negative.
Lies and misinformation, or choosing chatbots over therapy and relationships might sound scary, but as of now I see practically negligible impact there. Even social media is still roughly as usable as before AI.