Sorry if it's been said already, but "stoop life" has been a thing in inner cities for... well, forever. It's more common with underprivileged communities in inner cities, so I can see how more affluent people would "suddenly discover" that hanging out on their stoop helps create community. In my experience, where the two intersect, it's usually the more affluent people pissed off that less-affluent (or perhaps "more culturally diverse"?) people are hanging out on the stoop. I've lived in DC, Baltimore, Philadelphia, and NYC, in multiple neighborhoods in each city, and I assure you, "stoop life" is everywhere,
except on the wealthier stoops. But it doesn't have to be that way.
Another thing that helps create community is stoop gardens. People will stop and gather round a stoop garden to marvel at what's being grown. Neighbors will lean out their window to yell a hello at a stoop gardener. I can't recommend it enough.