The government regulators also have an interest in knowing the laptops they buy for eg the NSA have authenticated parts to avoid supply chain attacks.
If you're selling cell phones you already spend plenty of time satisfying regulators and vendors from all over the world. The cell phone companies aren't the ones with power here. (In general tech people have no political power because none of them have any social skills.)
Supply chain attacks don't generally target the second hand market. Much more effective to upstream your attack to the vendor Apple buys parts from in China, and compromise every MacBook in one fell swoop
That's too discoverable to work. Supply chain attacks are by state actors who can interrupt specifically your order on its way to you and silently replace parts in it.
If you're selling cell phones you already spend plenty of time satisfying regulators and vendors from all over the world. The cell phone companies aren't the ones with power here. (In general tech people have no political power because none of them have any social skills.)