Well, lets see...
Certainly, your statement: "Angry birds is as good as it gets" is nothing short of, well, silly really. Mobile GPU's are going to get very powerful, and mobile gaming will become one of the biggest sources of development in the world. It's inevitable.
Lol, 7 or 8 years ago? so like I said, not comparable.
Can you really see an iPad being capable of playing Arkham City any time soon? so like I said, not comparable.
Yeah, tablets have a place, but yeah they might eventually replace desktops, but not anytime soon.
Touch screen gaming is just like the current fad of 3D TV's as in....temporary
And yeah, in the future we probably will have total immersion gaming, in the next 5 years? not even close, tablets are good for casual gaming e.g when you're traveling, and thats only because they're portable, I'd still rather play Red Alert 3 on a laptop on a than the crappy iPad version