Jack-B,
Thank you for your comments, though I think we are already more or less in agreement!
I do have some friends, but could definitely need some more. However, my main objective with my post was to highlight the fact that it generally does get harder to make friends as the years go by. Think of this formula: I know this is a simplification, but please indulge me:
(number of potential friends in your environment) + (effort) + (luck) - (anxiety) = overall chance of finding a friend
My point is that the first variable falls drastically as you get older, since people settle and are simply not interested in finding new friends. So, even if your anxiety is somewhat reduced, the pool of potential friends dwindles too quickly. That means your effort must be increased to compensate. My advice: try to make friends as early as possible, as it will not get any easier later. Look at kids, one trip to the playground and they've found a new friend! Of course, many of us here at SPW have suffered from anxiety and shyness most of our lives and so these crucial early years didn't produce any life-time friendships. I myself met my best friend only 10 years ago.
True story: If I'd had the confidence to talk to strangers that I have now back when I was, say, 15, then I dare say I would have gained many more friends than I did. Not saying it's impossible now, just harder. Like, at work, I can speak relatively comfortably with most people (not in larger groups, though), but that's where it ends, most of the time. They got wife+kids+a circle of friends already and are content with that.
It's good that you find it easier to make new friends, but you're still in your twenties, Jack. Back when I was your age I was at university, and indeed, the pool of potential friends was incomparably larger in that situation.