> Once a thief has stolen his 10th iPhone that he can't do anything with, he'll probably be less likely to bother stealing iPhones. If anything it's a liability since it can be tracked as long as it still has some battery.

Theft isn't just for the whole device, it's also for parts. By making the part market so difficult they essentially create a black market for it in third world countries where just the phone's battery could be worth a day's wages.

You have a lot of faith in the learning curve of a thief. In my area, the ATT fiber lines have been cut multiple times in the same area multiple times directly impacting my my friend's service. These have been due to the lines getting cut searching for copper. They still haven't learned and it keeps happening.

This is assuming that the thief can tell which phone brand/model it is at the time of theft.

For phones which are in a case/cover, inside bags etc., it seems almost impossible so am unsure that this is an effective deterrent.