I've never been super popular or great at making lots of friends, but I found that once I was no longer in college being surrounded by people that were more like me (in school, around my age, etc) it got harder. I still made friends at my job, but it really only happened once there was an influx of recent college graduates. When that job went away, it got harder again, as my next jobs were a more varied group of people, including plenty of middle-aged parents. Being childfree, parents are hard to make friends with because of their kids' schedules. It's been around 10 years since I last made an IRL friend.
So I guess what I'm saying is: I'd like to know also.