He corroborates your point regarding not discriminating the phone he stole, to be fair.
But your point is valid, and I can understand why you hold that opinion.
I take it you’ve never been to an impoverished area? Holding an iphone paints a massive target on your back.
It doesn't matter. The market will dictate behaviour. As soon as the value of iPhone parts drops at the end of the chain (Shenzhen et. al) this will propagate all the way up to the street criminals.
Perhaps they will not discriminate by iPhone submodel (will not matter after a while of the serialisation policy), but they will (and do) discriminate by brand.
Much smartphone theft includes robbers grabbing the phone out of unsuspecting victims' hands, forcing them to surrender it at gunpoint, or pickpocketing it.
Apple has already created a pretty good deterrent to prevent iPhone theft - the Find My iPhone system. It’s better because it’s actually useful to the user and works even if you turn the phone off. The way I see it there’s absolutely no need to serialize the parts as an additional measure to prevent theft (given also what I said in the first paragraph)