This isn't really the case outside of far-flung suburbs and rural areas. Where I live, setbacks of more than 6 feet or so are rare, and front porches and stoops right off the heavily used sidewalks are the norm. We do "porch hangs" with our in-building neighbors, our kids and the kids in the neighboring buildings do sidewalk chalk together, we hang out at the local parks together, bring over friends from nearby neighborhoods, and talk with other parents and stuff.

Being a parent in a child-friendly neighborhood helps a ton with finding a community. Before we had a kid, we'd do things like welcome new neighbors with treats from our favorite bakery and our phone number if they needed anything, being generous with our time and things, etc.