Technological developments, throughout our long history, have played a positive role in eliminating existential threats to society
The "disbenefit" is that we'd lose out on similar potential positive effects. Although I don't know that any technological development has really eliminated existential threats, but they have certainly significantly improved quality of life and saved many lives.
all of the major existential threats are due to our technological developments
Such as?
The main/only existential threat I can think of right now (that's a result of technological development) is climate change. But that's been around for quite a while, and further technological developments have given us methods to mitigate that. The biggest hurdles to adopting those has not been technological, but rather social and political, and significant pushback from those heavily profiting from fossil fuels.
Social media might be another, in that it seems to have some very bad downsides, but it also allows people to connect with people like them and share things that wouldn't otherwise be seen by many people. It probably also would've been really hard to predict or proactively prevent the downsides.
moving more slowly should ensure that technology is developed responsibly
I don't think it's a particularly realistic view that we can just "slow down" development.
You'd need widespread global coordination, which doesn't seem plausible. If you don't have that, the people who agree to slow down will just fall behind people who don't, while possibly not affecting development much, and letting it be led by people who aren't that concerned about harm they may do.
And even if you could get this coordination, you may lag behind bad actors, who could invest more heavily into reaching subsequent milestones, and our intentional lagging could cripple our ability to deal with that.
This idea is probably best demonstrated in information security, where researchers very actively look for problems in security technologies, so that they find those problems before hackers do, and warn people and publish about it, so that it can be fixed. If hackers find it first, that's bad.
There isn't a dial somewhere which you can just turn to affect the rate of development. Money is probably the closest parallel, but it's not a perfect comparison. The whole crux of new discoveries is that they are discoveries: we didn't know they were there. We could invest trillions more into AI and not make any new revolutionary discoveries, or we could invest a tiny, tiny fraction of that and discover a whole host of world-redefining things.
Money will probably be correlated to how quickly we discover new things, but we can't really predict what the future will hold.
I also think it's a bit naive to think we'd develop things more responsibly if we slow down.
People just haven't been very good at developing things responsibly.
Much of the problems from AI also came from relatively small developments or things we likely wouldn't have foreseen. ChatGPT and deepfakes were both built on decades of work by countless people. Those may not have been trivial steps forward, but they were probably small enough that we couldn't have "frozen" development prior to their development, or in the middle, in order to prepare, even if we did see that coming.
Are there more problematic developments coming? When?
AI has already been very disruptive, and primarily from 2 or 3 big developments (which use somewhat similar widely-used technologies), so it's unclear whether trying to slow it down at this point makes much sense.
Ethical development and use of AI?
Ethics in AI has become an increasingly prominent and important topic. Plenty of people do think about these sorts of things.
Deepfakes may be an example of something where we could've seen the risks, and there weren't that many upsides (although people do like realism in entertainment). So maybe the ethical choice would've been to avoid advancing research in that direction. Although it's built on technology that would've existed with or without it, so someone probably could've developed it in any case.
That said, I don't know that there are many examples where the development itself could be viewed like this. Usually the focus is instead on how AI is used.
Although I would say that people should consider the ethical implications of what they're developing and how they release it, they should work with lawmakers to mitigate potential or realised downsides, and lawmakers should actually do their jobs and create laws and regulation.
None of this necessarily involves "slowing down" progress by a significant degree, and it'd probably be a lot more effective at mitigating downsides of new technology than merely trying to slow down progress.
Whenever people object to AI development, I think of people objecting to the industrial revolution.
It came with a lot of problems, climate change probably being the biggest. But we didn't know about that at the time, and despite this, we had plenty of very clear evidence of the emerging downsides, and how to mitigate them, but that was mostly ignored. Slowing it down probably also would've meant the effects would've taken longer to emerge, and thus we would've taken longer to notice it... and people would've been even less concerned about the effects, since the sudden massive spike in global temperature would've been a bit less massive.
It also made huge improvements to society that may not otherwise have been possible.
People were objecting to jobs being lost, but it created many new jobs and the upsides were much greater.
I don't know that you'd find many people who'd argue that it would've been better to "slow down" the industrial revolution, or that it would even have been viable to do so.
If there is any lesson to be learnt from the industrial revolution and climate change, it's that we need to pay more attention to things that are clearly visible, and actually do something about it (and listen to experts). And we should possibly be more proactive about trying to predict the effects of our actions, but we already pay a lot more attention to that, and that doesn't necessarily mean slowing down.