Your car analogy sounds a lot like Tesla with phone-as-key, and last I checked Tesla sold 500k of those last year and are on track to sell 800k this year. People have been locked out of their Teslas when their phone is dead and they didn't bring a physical key with them.
Apple adds these arbitrary digital locks since they protect against the threat model of physical access, whether that be an attack thanks to leaving the phone unlocked or giving your passcode to your friend to use for a while. This is all in disregardless of whether or not the customer actually has this as part of their personal threat model.
Adding an optional "You phone us and we can unlock your car with a copy of your key" is fine by me. As long as I still have the fucking key.
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For the second part - The security boogey man is not a compelling argument to give up ownership rights and enter digital serfdom where you only own a device if you use it in the way the manufacturer intends and approves of.
I'm not asking them to stop selling devices with locks. Hell, I'm even fine with them keeping a copy of the keys (which they have right now). I'm just saying: As the owner of a computer, I deserve to have a copy of the fucking keys that make it work.
My point is that, Short of an actual physical key, by giving the user the key, they give everyone the key to do this to any iPhone in their possession, regardless of ownership. Any regulatory change shouldn't nullify Find My iPhone protections to the point that theft of iPhones becomes lucrative again.
Apple adds these arbitrary digital locks since they protect against the threat model of physical access, whether that be an attack thanks to leaving the phone unlocked or giving your passcode to your friend to use for a while. This is all in disregardless of whether or not the customer actually has this as part of their personal threat model.