Because it is a trade off between the largest, consistent screen size, having a front camera, and a notch (that's how we call it, this is the first time I see the term cutoff).

I dislike the notch, but it isn't very annoying. You still got your status stuff on the top left and right. However, if I'd be having my device in landscape it'd thoroughly annoy me no matter what. It destroys the device symmetry!! However landscape is a niche for me; I don't watch many videos.

I do think your comment hits the nail though. Apple gets away with all kind of innovations: TouchBar, butterfly keyboard, no 3.5 mm...

The notch is in a separate category. It was definitely a natural necessary technical compromise. For ergonomic reasons, a phone can only be so large, but you also want the screen as large as possible. There is an argument to be made for getting rid of the headphone jack to increase the room available in the phone.

The butterfly keyboard was an unnecessary attempt at thinness. The laptop did not need to be thinner for ergonomic reasons.

The touchbsr generates a lot of nerd rage but most people don’t really care about the function keys.

Some phones which had 3.5mm jack removed have been opened; they actually easily had room for the jack.