I get the prison part. But you do keep in contact for a while after University, right? Until friendship slowly fades out because of distance or marriage or kids, no?

It's from the perspective of someone from a country where people have traditionally gone to university a long way from home, so distance (also, I left university before social media, so a lot more overhead involved in keeping in touch back then).

Guess so. I grew up in Belgium. University was only 1 hour by train or car drive away. It didn't matter which one I picked. I still see my friends from uni occasionally once a year after 20 years.

Living in Belgium does odd things to your sense of distance, but it still increases your chances of just bumping into people by chance more often.

I come from just outside London and studied in Hull. Three years after that I was living in Brussels and only in contact with three or four people from university.