This sounds nice until you actually look at most of America. Cities are designed around cars. I'm in a rather walkable city and the nearest grocery store is a mile away. That's not too bad, but other places I've lived it is 5+. Buses are bad (hour+ between pickups) or non-existent. It gets difficult to do all kinds of chores, visit the doctor or whatever. Even using a bike my grocery store shopping becomes a multi-hour experience that I have to do more than once a week where a car is 30 minutes and once every week because I can carry more. The experience is completely different in a city where I would rather actually walk than take a car. I don't think this is an uncommon experience either. What I'm trying to say is that it isn't great to just tell people to start walking but rather to recognize the design and incentives places by that design. The burdens that it creates. If you want people to walk more for their commutes then you need to design cities for walking. I've lived in many places in America where sidewalks are non-existent. If you live in these places and walk you either have a death wish or a DUI. But rather, build it and they will walk.