Pairing components doesn't make the device theft proof.

Overwhelmingly phones are stolen and sold as-is, not chop shopped. Chop shopping is generally not a lucrative business because availability of 3rd party parts is a lower cost than the time required to disassemble.

The availability of manufactured parts significantly out scales independent sales.

Contrary to common thought, Apple has a particular issue wherein they are focused upon for repair because their vertical integration results in few models. Less models = more focus on methods to repair.

This means that apples intentional methods to prevent repair are not for your benefit, they're for profits. You can have security and repair.