Read a recent comment on the decline of Facebook.
It's just like any other innovation. And you don't need to be an expert or an analyst. Someone paid to have an opinion on tech matters. People will always want something else. Facebook takes time. And for many it takes a lot of time. Now unless I become an addict, I realize, "Hey?! Where did my life go." ...and Facebook...done. I need something less time consuming and just as falsely fulfilling. Who has that for me?
As an experiment: If you know any high school kids, then ask a few about what they use to say meaningless things to people they may or may not actually know. I suspect you will find not many mention the billion dollar advertising machine that is Facebook. So if current high schoolers don't care what ten year future is there, at least for now?
Ask yourself then. What do these social sites make? Your answer I suspect will reveal they make nothing. And with the other tools available to you, you can do without any of the connectedness social media provides.
All of us know, there is no reality to hundreds of friends, thousands of followers, millions of views. You know the people you see. And you know the people you talk to every day day.
What is the next innovation in social media? A face to face conversation.