Maybe the simple fact that streaming apps is pretty idiotic.
Imagine the scenario: I want to check tomorrow's weather on my beautiful new Apple TV. I reach over, grab my iPhone and fire up the Weather App. Hey look, it says it's going to rain tomorrow. I move to push the button to Airplay it over to the Apple TV. Then it occurs to me, why would I bother when I already know they're calling for rain? Now why did I buy this overpriced TV again?
Video apps are even more idiotic. Stream the video to your iOS device. Hit Airplay and now double stream it, first from the web to the device and now from the device to the TV. Yes, that makes sense.
Or how about all the apps that make no sense on a TV screen? Do I really want to mess around with Pages or iPhoto on the TV? Or playing touch based games. Yay, it's up on the big screen, but I'm still staring at the small screen to have any hope of playing!