I could see Facebook charging business pages to make sure their posts, which are often advertisements, get seen. But charging the everyday user? Might as well ask people to leave.
And where would they go? I've never heard anyone in my circle of friends, family and colleague talk about using Google+ or any other social media site that has any importance.
Facebook is the juggernaut and if you like social networking and the stuff FB offers then there's no going around it.. there's just no realistic alternative because of the user count. Facebook has around 800 million users and that alone ensures it keeps its customers because it's the key to their success.
So for some Facebook has become equally, if not more, important than their telephone or mobile and if Facebook starts charging small feels for this or that feature people will bitch and moan but they will pay because there's nowhere else to go.