I have found that Discord has become the closest contemporary thing to the old communities you talk about.
Many niche interests now have small Discord servers with like minded people, and if you hang around long enough you will become integrated with one of these niche communities.
I have been a part of several Discord servers for 5 years and I feel like they truly are communities: there is a deep history of the active members; people who met on Discord have visited each other in real life; members have gotten married; members have shared in grief as other members committed suicide; over time people have come and gone, but they have always had the Discord community to come back to when a relationship falls through, or they just need companionship in a tough time.
I have found that Discord has become the closest contemporary thing to the old communities you talk about.
Many niche interests now have small Discord servers with like minded people, and if you hang around long enough you will become integrated with one of these niche communities.
I have been a part of several Discord servers for 5 years and I feel like they truly are communities: there is a deep history of the active members; people who met on Discord have visited each other in real life; members have gotten married; members have shared in grief as other members committed suicide; over time people have come and gone, but they have always had the Discord community to come back to when a relationship falls through, or they just need companionship in a tough time.