I think the analogy is a bit off. I don't expect to mess around with my car the same way I do with my phone. A messed up software setup in a car can actually kill me instead of just having to restore from recovery in a phone. Purpose of phones have expanded greatly from just making calls and receiving messages to being in the center of our digital activities which means my expectations there have greatly grown and Linux fills the gap of freedom/flexibility. However, irrespective of the software, a car's overarching purpose is still getting one from point A to B; sure, great if I can also ssh into it but that is way lower down the usual list of things you expect to do with your car.