Oddly enough, most of the critics who said the same thing are starting to change their minds now that they are realizing the power of social circles on Google+. I've seen at least a dozen within the last week alone praising Google+ after bashing it last month.
Honestly, Facebook and Google+ won't emerge as the dominate social platform within 5 years simply because of the recent and surging push for more privacy. If you followed the link in the second post, there's a few good links in the comments of all the shady shit Facebook is doing with your personal data on facebook.
They're spying for the CIA and selling the data off to other big companies for other nefarious purposes, Google isn't much better but at least you know and expect that going in and they'll keep it to themselves to push you more Adwords ads later.
Oh, and when you "delete" a FB account, it's not really deleted, they can activate it anytime to check the data, even though you won't ever be able to touch it again.
All that above is why it's going to be something radical that replaces Facebook. I do see Google+ making a large dent and opening up the market to other stuff, which is Google's whole reason for this anyway, but it won't be what comes out on top.
Yeah, FB is unethical as far personal data is concerned. But anyway, social networks are trying to evolve social experience but they all end up pushing to users the same stuff and selling them to big players.