The downside of being able to stream whatever you want whenever you want: reduced social interaction around the television set.
I see instant streaming as both more and less of a waste of time than live television used to be. On one hand if I’m going to just chill (“waste time”), it’s handy that I have access to “good” (critically-acclaimed or educational) television to digest at all times instead of wanting to chillax and puttering around aimlessly. On the other hand, when there was nothing to watch on TV, I used to putter around with friends, or find friends. Now, I have less need for human interaction — especially with people whose tastes differ from mine. I think this trend has been crystallizing in more ways than television in our society.