Which things other than phones are primarily stolen specifically to be parted out (and...to be perfectly honest I'm not sure I buy that it's even that big a thing in phones)? And which companies have made the problem worse by artificially restricting part supplies?
Cars being stolen to chop shops is a thing, I am extremely skeptical that it's the primary reason cars are stolen.\
-edit- Yeah even according to your source, a pretty tiny minority appear to be stolen for parts. Probably because, as you point out, parts are so easy and relatively cheap to get, except for inherently valuable parts like catalytic converters. And guess what? If people start stealing iPhones to harvest the gold/rare metals, parts pairing is not going to fix that.
If you were taking about theft in general, then I don't even know what point you were trying to make.
And yes, other companies selling fewer official parts (although I've never been unable to get screens, batteries, or replacement charging parts for my non-apple phones) is bad, and I already criticize companies that fail to make parts available. When they start doing part pairing, I will criticize them for it to. The fact that this behavior is bad has nothing to do with it being Apple. Not making parts easy to get: bad. Making replacement parts not viable without input from manufacturer: also bad.