I am 28 and my friend group has been slowly falling apart for the past 3 years

Every few days I get a phone call from an old friend. This friend tells me about a friend in our group who has completely estranged themselves from the rest of us. This group was like a second family to me since I was an only child and never really fitted into any group. But every few days I hear that another member of the group has just disappeared that I'm starting to feel like I'm living in a bad episode of The Leftovers.<br><br>This morning it was the call about my best friend since senior school. Who I've known since I was 14 and used to just spend countless hours in my bedroom talking to. Who I've known since before I fell. And it's another person I've lost. I'm 28. At what point do I just accept that if I want to see these people again that I'm going to have to make the effort to make it happen.<br><br>How do people maintain long term friendships?