I’m from Germany so I can’t comment on the exact dynamics of American suburbia but I grew up in a medium to small town in a single family House and we were regularly in contact with the neighbors. Eventually I moved out into the next big city and in the apartment complex that I moved into it’s completely anonymous and no contact between neighbors except the occasional head nod.

I live in a suburb by a major city in the US, and know so many neighbors. The sense of community is really strong. I help my neighbors remove snow and take their trash out as they are old.

I feel like some people are just making assumptions or are extremely introverted.

This has largely been my experience as well but in the US. However, a new couple moved in next door to my apartment. We’ve done happy hour with them and I share the fruits of my cooking/baking adventures. Stop and chat when we are not in a hurry. For whatever reason we’ve not gotten to be much closer than friendly neighbors. Could be the woes of young professionals in their 30s without kids but the effort definitely feels greater than at other points of life.