We have sidewalks on our street and on streets built-out after us. The street just south of us (in the same subdivision) is just a few years older and they don't have sidewalks. It doesn't get as much foot traffic, though Sophie and I do walk it occasionally (out in the street).
Foot traffic around us seems to be a very strong function of homeowners with dogs - much stronger than the number of homes with kids. Dog ownership has been on a steady rise in our neighborhood over the last decade or so. Maybe that's the secret!
Cheers,
Scott.