There's a bit of a disconnect here in that many on this forum are software engineers, probably mostly working on systems that need no hands-on interaction (or on apps that can be tested easily locally).
The products you listed are hardware products (with integrated software) which are much more difficult to work on remotely, especially in a company that prioritizes secrecy as much as Apple does.
Apple software engineers who work with prototypes did this for two whole product development cycles. Access to prototypes _can_ still be managed remotely, it turns out.
It's possible to do (I'm doing it), but it's definitely more complicated than in-person, especially when operating across a team.
From a hardware engineering perspective, access to equipment is also important; I have a decent lab setup at home, but I've still needed to go into the office regularly to access some testing tools.
