There are places you go because you have to be there. Work. The grocery store. The dentist. There are places you go because they are yours. Home. And then there are the places in between.
Sociologist Ray Oldenburg popularized the term third place for informal gathering spaces outside home and work: cafés, pubs, barber shops, libraries, parks, stoops, community centers.
One of the quiet changes in modern adulthood is that friendship often requires administration. Compare calendars. Pick a date. Make a reservation. Confirm the reservation. Third places lower that burden. You go because you go. Other people do too.
A city can be crowded and still feel lonely. Density is not the same as connection. Thousands of people can live near one another while moving between private homes, cars, offices, and transactional spaces without developing much sense of shared life.
Community is difficult to build if there is nowhere to casually encounter it.
Maybe the answer is not to recreate some idealized neighborhood past. It is to design more reasons for people to remain in public together.