This thread is kind of sloppy because a lot of people on here don't know what a launcher is. The bottom line is, this isn't being forced on anyone from any platform. It's an option, and furthermore it's one you'll have to install in the first place.
As far as Apple doing it? No. They played nice with FB long enough to get the integration into iOS and I think that's as far as it goes. As far as the "social center" idea for an Apple app- there are third party apps that already organize your multiple networks into one feed.
iOS 7 is probably going to look exactly like iOS 6. Apple has of course made changes to iOS over the years, but the tend to keep the actual image of iOS very consistent. I'm all for some major tweaks, but if they ever actually do it, I'm sure it will all be gesture based and keep the actual UI and image the same.