Most people are very impressed with AI. That's why adoption for performing so many things is as rapid as it is.
Operating systems is one of the few places where direct AI integration makes little sense. The sole job of operating system is the function as something that connects hardware you have to software you are running. It needs to be maximally predictable by both, so things you actually need running, software that runs on top of the operating system is as stable and as fast as possible.
Agentic OS is the opposite of that. It's a permanent moving target. So it may be better at whatever features you want to push as the OS maker, but it's strictly worse as an OS because it's inherently less stable.
This was actually very visible in one of the removed MS demos, where they ask agentic part of OS to resize text, and instead get instructions on how to resize the UI.
Now imagine the same thing, but with OS doing it for you. Suddenly a lot of things become unusable because UI is either massive or tiny instead of just resizing text.
Now imagine the same but with addressing hardware. You'll be lucky if the whole thing just crashes and restores itself on reboot.