I worked at Apple from 2014 to 2016 and the iPhone, iPad, etc. teams I was working with were in offices, one or two to an office, up until a big move to an open office in early 2016. They appeared to have been in offices for years.

Apple is sufficiently secretive that indeed some other teams might have been in open offices. Not the ones that I saw or interacted with. I was working on a key part of the iPhone and iPad technology.