The truth is you need a place to put people (and data in the CPU world) while they are going about their lives and moving from place to place.
To move from place to place, it seems the average American prefers their car, since it generally runs on their timetable, and they do not have to share personal space with strangers.
And it is not just an American thing. If you look at developing countries like India and China, car ownership and usage is exploding as people grow wealthier.