[1] https://www.seangoedecke.com/they-really-do-think-ai-might-k...
There is quite a lot of mathematical research into agentic behavior that suggests a combination of instrumental convergence and the orthogonality thesis make it very likely a superintelligent agent will have arbitrary goals that lead it to attempting a takeover of Earth's resources to achieve them.
There can't be a science of superintelligence because it doesn't exist yet, but the best theories I have read seem sound, similar to how 19th century theories of anthropogenic climate change turned out to be sound.
So it all hinges on an empirical disagreement you have with them. There's nothing particularly unserious about that.
Even the sci-fi scenario assumes there is a discrepancy of capability between attacker or defender. If the 'attacking' system is (by some reasonable measure), 1000% as capable as a human, and the 'defending' systems are 60%, then it is a problem. If the 'attacking' system is 1000% as capable as a human, but there are hundreds of thousands of systems that are 900% as capable as a human, it's probably not going to take over everything successfully.
So unequal distribution of AI technology, and lax regulation and opacity of the biggest companies which actually make the risks the worst.
I don't think the "AI Safety" people are "unserious and out of touch" - I think they are actively making AI Safety problems worse by being advocates for consolidation of AI development and lack of transparency.
But those things fall in a category of "things that are awful and I'd like to see solved", which is different than "existential risks which could see my kids dead, and there's nothing I can personally do to shield them from it".
We should be paying at least as much attention to the people who want to use AI to consolidate their wealth and power, and how they’re trying to do that. They’re a clear and present immediate danger to our societies, not something we can only speculate about. And if we deal with them, better control of AI will be a side effect.