That being said, we live in a relatively rural place and I see a lot of people struggle with loneliness. It's not as simple as "joining a group" when there aren't any around. Maybe you could go to a bar, but the people at the bar are mostly older townies (we're mid-20s to early-30s). Plus, going to bars is less fun when you have to think about driving home. They could go to church, but most people around my age aren't religious, and the few people who do go to Church around here tend to live very faith-focused lives.
I guess the ultimate solution is to leave their hometowns. I've pushed several of them to go back to school as a method of getting out of their situations and meeting people, and it's honestly been kind of successful. We live in NY, so school is free if you meet certain economic requirements. It's been great to see them flourish.