I think most adults would agree that it can be tough making new friends. And according to new research, the average American adult hasn't made a new friend in 5 years!
Your "popularity" in terms of the number of friends you have hits its peak at about age 23, and tapers off from there. By the time you hit your thirties, you'll have about 3 "best friends," 5 "good friends," and then a whole bunch of people you know but don't actually socialize with. (guilty as charged)
I think the exception is if you have a job where you're constantly meeting new clients or vendors. In radio, we meet new people all the time, but my husband, for example, works with the same people day after day, so there's not much opportunity to meet new friends.
The study also found that adults in their 30s and beyond aren't very likely to engage in activities that would allow them to meet new people with similar interests--like joining a club or sports league--because of job and family commitments. However, that is a great way to make new friends with similar interests! And 45% of adults say they would welcome ideas for ways to meet people that don't involve the bar scene.