I was using iMessage as an example of something tedious and not overly complex but not exactly low hanging fruit that's yet to be completely reversed. The S/N or certificate parts don't even matter, if people had reversed their way through it, there would be at least an option to extract the required parameters out of your hardware and plug them in a stand alone server (in fact, IIRC there a valid S/N generator some time ago that was used to deploy osx in kvm?).
So, the idea is that even though it's not an impenetrable fortress, there are still plenty of dark places to introduce subreptious changes.
As for the human-in-the-loop part, I don't know why did you get so snarky, what I was talking about was that this is the layer that should be scrutinized the most, all of those components because even without the technology those are the people that will put someone in jail with no verifiable evidence.