And you can take approximately 3 seconds to click on the kill switch if you so desperately need not to see an AI button somewhere.
Like I can understand (and I agree) the stance on AI in general, but this is just a knee jerk reaction. Your browsing experience is 99.9% unchanged even if there is a button somewhere…

Nobody wanted AI as a feature

This is false, you don’t speak for everybody and represent a small vocal minority of users.

It already is a broader ecosystem of trusted software. Have you looked at what is inside a modern browser? It’s not 1999 anymore, and tons of related stuff is embedded in a browser.

So if you never press the AI button, it’s never enabled. It is opt-in in the strictest semantic sense.
What you say here applies for things that run automatically, like the anonymous usage reports, which is opt out, not for things you activate yourself.