I don't know what you mean by 'robust'. What I'm saying is that I used to have a satisfactory social life - on the order of parties or other similar events call it once a month more or less and "let's get together for beers" or similar on a reasonably regular basis besides - which in essence no longer exists.
I can certainly understand that it seems kind of incredible to you. It seems extremely incredible to me! I still haven't quite got wholly around it. And, yes, I can "just" call people up, or text or email them, and sometimes even get a response. I still occasionally do so, and still occasionally get together with one or two people at a time for a few drinks and to catch up. The problem comes in where you try to organize something on a larger scale, or where someone else does so. It would be technically inaccurate to say that to do so is impossible without using Facebook. But I've certainly found it ineffective to try to set things up via email, which was not the case a couple of years ago.
I would not be surprised to learn that I'm as old as, or older than, you are. Most of the people in my former social circle are somewhat older than I am. I'm pretty sure this isn't just a "people in their twenties" thing.
(Edited to add that I don't understand why you're getting downvoted, and I wish people wouldn't without explaining why they're doing so. Certainly, if it's out of some misguided assumption that I've chosen to put myself and my experience out there without being prepared to address people who express entirely reasonable incredulity and doubt about my veracity, let me take a moment to note that such action on my behalf, while certainly appreciated, is entirely unnecessary.)
