Angry Birds, in a sane world, should be worth no where near one billion. They have sold less than 100 million copies, and I doubt they can keep on repeating their success year after year. It's a fad that will soon be replaced, just like Doodle Jump and Flight Control before it.
I don't know. I don't think Angry Birds is an interesting game, but it's obviously blowing up like mad, so I don't pretend that any rational dictum will predict that it dies down.
You don't see plushies and fan art for the other games - and you shouldn't ignore all the ways the creators profit from the franchise. They also make a bunch of themed releases like Halloween. They may also have hit a tweenage demographic susceptible to crap like Silly Bandz, Bratz, and other inane ztuff.
You've missed the point. Sure, it's 'blowing up like mad' but the important thing is that Roxio have been able to turn the Angry Birds game into a brand: selling movie rights (!) something even EA struggle with, so quickly, getting a deal with FOX for marketing and developing a range of real-world merch to go along.
All on the back of one simple little app that looks and feels like a flash game. (i love it, don't get me wrong, but it is not anything special)
Did Harbor Master or Flight Control do this? No.
It takes a lot to think big and that's where the big players are-- and worth a good chunk of money too.