The bullet points ("Is the documentation team not given the time..." etc.) apply to a lot of tech companies. "politics or in-fighting" and "not considered a prerequisite for shipping" hit especially close to home.
Not that it's an excuse for anything Apple does, but technical docs are an afterthought at all levels across the board at software companies, and the few places that do them well stand out much more than the many that botch them.
IME that's really the one, at none of my jobs have releases been really urgent, but writing or updating documentation was never really part of any sort of process. To the extent that it existed it was something you'd task one or two persons once in a while, but one or two not-professional-writers can't document the production of dozens of devs and do their own dev.
Producing documentation is looking down upon, it's not factored in any development, it's not part of any development process, and it's not part of any training. Most people also don't enjoy writing documentation, though I couldn't say whether it's because they simply have no training / encouragement for it, or genuine primal dislike.
Not that it's an excuse for anything Apple does, but technical docs are an afterthought at all levels across the board at software companies, and the few places that do them well stand out much more than the many that botch them.