That’s a shame; I’m have remained close friends with a couple of dozen dorm- and lab- mates even after 35 years. Even started a company with one 20 years ago.

And we were all non-gregarious nerds. I wonder if that is why?

My university was quite large, with about 4,000 undergrads and about the same number of grad students. My high school was about 40 students a year (240 total) and I am barely in contact with any of them.