What’s laughable are the “terminator” scenarios where it suddenly comes to life in an instant and in that moment already has the power to wipe us out, and then does so.
A more likely scenario is that we come to rely heavily on AI more and more as time goes by, until it truly does have a grip on resource supply chains, manufacturing facilities, energy plants, etc. And I don’t just mean that machine learning gets used in all of those contexts because we are already there. I’m talking about custodial authority. We’ve ceded those duties to it in large part - can’t do those jobs without AI.
Then a malicious AI could put a real squeeze on humanity. It wouldn’t need to be a global war. Just enough disruption that we starve and begin to war among ourselves. Has anyone ever noticed how many of us there are now? Our population would absolutely fall apart without our massive industrial and agricultural complexes running full time.