On these new models the notch will rotate with the screen orientation, so you always have one centered in the top middle of your screen.
Perhaps the iPod nano is the thinnest possible, perhaps it’s not. USB-C requires a 2.5mm opening, not including the port housing. So we’re still talking about a 1mm difference. You’re saying an LCD display can be 1.5mm. So that’s 5mm with the headphone jack, with almost 1mm to accomodate the casing and port housing, the extra depth can be carved out of the case thickness if necessary. And that’s assuming we really are restricted to 5.86mm. But here’s the rub, if Apple reduced the thickness by .5mm in lieu of leaving the headphone jack, I’d call that a poor exchange.
The problem with reducing the iPad to one port, basically makes any serious audio work more problematic, requiring the purchase of additional dongles, and makes it less of a portable, self-contained solution, compared to the MacBook, when the inclusion of a simple port and less than another mm to accomodate it would solve the problem. Who knows, perhaps Apple will introduce low latency technology in their wireless devices, with uncompressed audio. But I doubt it.
Maybe the extra two are iPad Mini Pros? (Yes that’s a joke)