In addition to the sibling complaint about using a real monitor / closed laptop--which I do constantly, making my primary display a third-party panel from Samsung--I guess I disagree that a fix that would require retrofitting a new LED that didn't exist into a piece of hardware could ever be "trivial" in the way my suggested software update could be (but then again, I am not a hardware person, so maybe there is some kind of cheap, magic LED sticker they make these days that Apple could offer people for free at the Apple Store).
Or just have an actual physical LED nearby, maybe in the notch. They're cheap too, we decorate Christmas trees with them these days.