That Google gets too keep all their code private but a car company can't (due to the rather arbitrary fact that it's impractical for the car to ask a server how to change the engine parameters)
How about if I want to buy a device and agree to not see the code? (b/c for instance - I personally - have no interest in it) Should I not be allowed to enter such a contract with a company?
If yes, why is a company not allowed to sell devices exclusively with such licenses?
If not, why are you limiting the consumer's rights? (this rabbit hole simply leads to companies only leasing consumer's devices, b/c selling them suddenly involves giving away all your trade secrets)