Why Mac will never foreseeably converge with iOS
iOS is fragmented.
And no, before you start saying I'm crazy, I don't mean OS fragmentation. That's Android.
I mean in the sense that iOS doesn't integrate apps together.
If you (sorry) compare it to apps on Android, like custom launchers like Nova or Themer or Cover, these can integrate with your home/lockscreen.
Nova modifies your lockscreen
Themer lets you pick themes
Cover gives you the apps you need on your lockscreen
What can you do on iOS?
Change the wallpaper.
Now I realize that most people don't want to/ don't care about this. But this is about why it won't converge with OS X.
Because OS X has all the possibilities in the world (Because you can actually download things from the internet, while with iOS you can't even get two apps to work together.)
They are completely different, and unless Apple completely opens up iOS, they won't converge.
PS: You've probably guessed this, and now this seems retrospectively biased, but I use a Android (Galaxy Nexus) and and an rMBP