A great deal of places in the states have little-to-no shared (or public) greenspace within walking distance. It isn't just wealthy suburbs, but nearly entire cities. Small towns might have one such space. Larger cities (30-50k) had a few more, most were just small patches with playground equipment. Some towns I lived in actually had public green areas with playgrounds... that had no sidewalks or safe places to walk that led to them. The houses in the areas all had nice-sized yards, but I still found this curious.