Same for me. I was super tight with my friends for 4 years during my college experience. We were in every class together for 6 hours a day. Did everything together. Took a few years after graduating but now we don't hang out anymore. Maybe meet up once a year.
In Billy Baker's book "We Need To Hang Out", which is about trying to fix his lack of social connection as a middle-aged guy, he eventually realizes (spoilers!) that he should stop trying to reconnect with his college friends who are now widely scattered and instead focus on building new connections with the men around him -- that guy at Pilates who seems friendly, or a father of one of his kids' classmates. It's fun to revisit the college friends again, but they just can't be around for the week-to-week.
Almost all of my remaining long-time friends are people I made friends with at university. I keep in touch with just one friend from high school. Everybody else either disappeared off the map or reinvented themselves and therefore didn't want to maintain their old friendships past high school graduation.
