I'm from a big city, and what I've observed is most adults have little to no friends (aside from their workplace). They merely wake up, attend work by themselves, and go home by themselves. Most of their vacation is with their families. Is this to be expected? Nothing wrong with that of course.
This happened to me when I moved to a new city. Literally wake up, go to work and come back to a empty apartment. Repeat day after day. Spending my birthday alone in my apartment was definitely one of the more depressing times of my life.
But as others said life after University is an interesting scenario because up until that point our entire social life was handed to us on a plate and some of us are completely unaware on how to handle this after the fact. Most of us are not taught about this and usually only the certain personality types handle the change well and naturally bounce around new social circles. So if you're not in a job that leads to making lots of friends then you're screwed unless you take control and make things happened. (Working at some IT jobs can suck big time for work friends. I'm sure bar tending would have been a lot better in that aspect)