Another thing that comes to mind is the lack of front porches. If there were more front porches for folks as places for people to relax and chat with neighbors I think there would be more conversations started.
A director I used to work for lived at the end of a cul de sac where, in the summertime, everyone brought out a lawn chair and chatted away while the kids played. I think there needs to be a space for community that’s not as intimate as the inside of your home. That’s probably a contributing reason why, per @Chris ‘s article, people who lived near a park felt a greater sense of community.
Sadly, when the director moved into a more affluent neighborhood, they gained a beautiful big house but lost that sense of community.