Couple days ago I literally counted >100 varieties of marinara spaghetti sauce in the store. There's no way a walking-distance grocery is going to carry anywhere close to that (ripple effect on to all the people employed in making each specialty) AND do so at Walmart prices.

I live close to the grocery, and there's still no way I'm going to carry supplies for 4 that far (recall as a child doing similar with my mother, that was quite a trek made possible in part by not having a job).

Y'all who want pervasive public transit and no cars, yes I see your point - and really don't want to live that way. Do as you like, just don't do it in a way that compels non-urban living to comply. 'scuze me now, I have to get the kids from school - driving them because herds of children on mass transit is a haven for bullies.