Earlier quoted context omitted.
> It's pretty hard to just up and make friends in Japan Certainly not unique to Japan. I see many lonely people in western big cities for instance. Surprisingly, I find it much easier to find a girlfriend than a friend. You just go to a dating website, find someone "similar" and spend time together and you can get close very quickly. It's not the way regular friendship works where it takes much longer to get intimate…
> I see many lonely people in western big cities for instance Not true for Berlin, though. If you regularily visit some hackerspaces (or other meetups with like-minded people, such as various user groups such as Emacs user group, political groups such as FSFE, whatever), or go to university and study there, you have very good chances finding friends, some of whom may turn out to be very good friends. Sometimes it see…
I agree that what you described is a good way (maybe the only way) to make friends. But consider what proportion of attendees at those meetups ended up becoming your friends. I'm guessing a single digit percentage, at best.
For people who don't go to many social events/don't talk to many others there/don't deepen those ties as much, it's very easy to be lonely in basically any city. Making friends takes work, and success is not guaranteed; if you're not putting in that work for some reason, e.g. your personality, you'll end up without friends more likely than not.
Let me present my own anecdote: I grew up in Berlin, and I certainly met lots of new people through school, sports, study groups and so on, but I always kept those separate. If I were into golf, my fellow golfers would be my "golf people", nothing more. I don't tend to attempt conversations with strangers (or people I know, for that matter), so very few of those acquaintances even learned my name. In essence, I don't have any friends.
I wouldn't call myself lonely, though, since I'm happy that way. I wouldn't even know what I'd do with friends if I had any. But I'm pretty sure that there are lots of people (also in Berlin) who are living essentially the same friendless life as me and suffer for it.