From an economic perspective the thief doesn't have any incentive to steal the device in the first place.
Deservedly. If there was a normal market, or at least access to spare parts, there would be no need for donor devices.
The warehouses full of people in Shenzhen tearing down millions and millions of stolen iDevices would still be chugging along, inserting stolen parts into the supply chain.
Apple enforcing DRM on parts is very much a pro-consumer move, steadily taking us towards a world where a stolen iPhone will be worth nothing.