You can't beat physics. Sure, you can design things so that key facilities and services can be reached on foot, but you simply can't provide the same facilities that could be reached in a car radius vs walking radius.
Sure you can. I've seen it done numerous ways. France is a good example (above) - not only is the boulangerie 2 doors down, the others are literally within 10m away by walk. In Hong Kong, some of my friends lived in a tower where the grocery, post office, etc were all on the basement floor (and the elevators were unbelievably fast) - I swear it was the closest thing I'd ever seen in this world to Foundation/Trantor.
When thinking about a car, you also have to chalk-in parking and traffic. I bet you most people spend more than 10m door to door to their grocery store.
