I suppose there are differences here, for example the root-of-trust of a car still isn't accessible to you; you can't run your own ECU firmware unless you jailbreak your ECU. Luckily, that is generally not the main 'feature' of the car, and for most people a car isn't a brain-extension with private and personal aspects.

Keep in mind that this doesn't mean you shouldn't own or repair your stuff, but there are significant differences between products, and those differences aren't always clear.