Today, you have a vast variety of ways to explore any given hobby and yet you have an "epidemic of loneliness". My view is that this comes because lot of people don't actually have strong "special interests". You can see something like meetup with fairly vague activities informal, non-athletic hikes get lots of interest. Dungeons and Dragon in particular is nice because it doesn't require people to become experts or masters of any given field, there's no winners and so it's like a lot of specialized fields. But it still only appeals to some people. For a lot of people, the real lack is public space that isn't structured and I don't see library meeting rooms really helping there.