Larger homes filled with more electronic gadgets, I suspect. To a lot of people, if you have trouble staying cool in the summer, the answer is to throw more HVAC at it. It would never occur to people that maybe by planting a tree or putting up blinds could make a big difference.

I see lots of suburban developments not far from where I am. Lots of cul-de-sacs and so forth, and strip malls every so often. When I was a kid we had the corner neighborhood grocery that we oftentimes used. Mom would send one of us out on our bike to go get something or another - that in lieu of getting in the car and driving to the supermarket. Of course back then we only had one car, so I suppose there might have been some scheduling issues that may have played into this, but since we had the neighborhood store as a fallback it was never a huge issue.

All through my childhood we walked to and from school. Sometimes if one of my parents was heading to work at a time that could get us to school on time we would get a ride one way. The rest of the time we walked. As a kid I was never that athletic, but I never really started to get fat until I got a car.

The closest thing we have to neighborhood stores these days is a 7-11. Not at all the same of course, but as times change, these stores could change their product mix a bit and perhaps start to take on those old roles.