Earlier quoted context omitted.
That doesn't require strong AI, firefox reader view achieves that without strong AI. It even preserves article images nicely.
Reader view isn't perfect yet, which is probably why (useful as it is) most people don't use it. Also, as more readers use it, the ad industry will try to circumvent it, e.g, by tricks like turning part of the text into images, et cetera. Eventually, you will probably be better off by OCR'ing the rendered webpage (i.e., as the user sees it), and using AI to only keep the relevant text and images.
It's not perfect so people don't use it?
No, people don't use it because it has poor discover-ability and it isn't in other browsers, further reducing discover-ability.