alt Hacker Newscars are barely efficient in terms of time. In cost terms, cars are incredibly expensive once you add in infrastructure costs, insurance, fuel, the cost of land use, etc.
Public transit is efficient even outside areas of high density - see suburban Europe or India. Why are so many people here utterly car-brained?
Have you ever actually been to Europe? Public transit is pretty good in first-tier cities like Vienna / Stockholm / London where tourists spend most of their time. But out in the smaller cities and rural areas where regular people live there's very little public transit except for slow and inconvenient buses. So everyone drives. Or if they're too poor to afford a car then they just don't go anywhere.