You've clearly never lived in pedestrian friendly environment. The nearest transit spot in areas with good public transport is a 5 min walk max. The nearest shop or doctors/dentist or bar/restaurant is 10-15min max and as another poster said you can easily use a taxi in cases of illness.

Also on the point of cost, cars are incredibly expensive, especially in the US where everyone seems to have massive vehicles. If you live without one, in a pedestrian friendly area you'd find the costs of using a bus or subway would be a small fraction of your car costs.