That doesn't mean they don't exist, but the numbers are few and, as these things usually go, inconvenient to your apartment or condo. Especially, as is often the case with city dwellers, if you don't have a car. Keep in mind that not having a car means:
It often takes an hour or more to get to and from said supermarket on the bus. And in San Francisco, that can be $2.00 for each person coming and going;
Your purchases are limited to what you can carry. This means no whole watermelons, large juice bottles, or 5lb. bags of anything;
Travel time and temperature issues --- If it's a warm day and you have to take two buses (a common occurrence), kiss off buying frozen anything, especially ice cream.