> If you were able to swap out security components, you might be able to spoof messages

But Apple repair shops can do exactly that (unless they always replace the device whenever the screen is broken, but I doubt that). What's the purpose in this whole cryptographic integrity if a third party - certified or not - can violate it without leaving a trace? If I was a person who has to worry this much about their security I'd much prefer swapping the screen myself without involvement of people that can't even be honest about "water damage" most of the time.