What suburbs are you talking about? Whenever I see the topic discussed here, people always seem to be referring to some strawman neighborhood surrounded by desert and highway. And maybe that's true out west where land is sparse, but all the suburbs I've known have been places like Abington, PA. Look at it from street view. There's plenty of sidewalks, detached houses, shops and restaurants, big chain stores, small mom and pop stores, and train stations that take you downtown. You can start from anywhere on that map and make it to a supermarket within 20 minutes of walking.