It is said that driving is one of the most dangerous activities we do, but I think it's no coincidence that it's also one of the most liberating. It's a very pleasurable feeling to be able to get into a car and drive, controlling it as if it were an extension of your body.
The phrase "If all cars were autonomous" has a similar feeling to others like "if there was no crime" --- sounds good on the surface, but also has deeply authoritarian and dystopian implications.
Edit: there's also this, which is basically like Stallman's "Right to Read" but for self-driving cars: http://this.deakin.edu.au/lifestyle/car-wars