People are using AI.
Your argument is that AI cannot be a serious concern because it has major known limitations. But most of us are using it despite the major known limitations. So the existence of the known limitations is irrelevant to determining what level of harms are possible -- unless the known limitations are directly limiting the harms. In practice, it seems like most current harms, and many of the (not stupid) feared harms, are completely possible despite the known limitations. Sometimes even exacerbated by them. ("Sorry, you told me to never stop your insulin pump, but I stopped your insulin pump while diagnosing a test failure. I will record in my memory file that I must always... hello? user?")
The (not stupid) parenthetical might be too weaselly for you, but that's how I see the "AI is going to rise up and intentionally subjugate or exterminate humanity" brand of doomerism. While I don't think that's strictly impossible, there are so many other ways harms that are much more imminent and much harder to defend against, that it seems foolish (to me!) to worry about those.
If you can stop a problem by pulling out the plug, you don't have a real problem.
If you don't want to pull out the plug, you do have a real problem. (Don't want, or can't afford to, or can't be bothered to so extremely that you never will, or whatever.)
Trope circa 1950 not true, because of trope circa even earlier...
Whatever AI people have been saying for the last 70 years, AI capabilities have improved stupendously in the last 10 years and there is no sign of the rate of improvement slowing down. I would like to deny it, but I can't.