I do not think AppleTV is the same as that TV you are talking about. AppleTV turns that large screen in your living room that used to only get data from a cable into a large Internet-connected display that shows on-demand photos and video (soemtimes from those phones and tablets). In a sense, the TV just is the largest display in the house, in a place where it is convenient for multiple people to look at it from comfortable chairs.

Can you source that last claim? It's a rather large claim, and one I'm not willing to take on face value. I can believe that TV is fading, but that the under 30 crowd "mostly" watch video on those mediums is a bit of a stretch to me.