From Childhood’s End (1953) by Arthur C. Clarke:

Do you realize that every day something like five hundred hours of radio and TV pour out over the various channels? If you went to sleep and did nothing else, you could follow less than a twentieth of the entertainment that’s available at the turn of a switch! No wonder that people are becoming passive sponges — absorbing but never creating. Did you know that the average viewing time per person is now three hours a day? Soon people won’t be living their own lives any more. It will be a full-time job keeping up with the various family serials on TV!

For some previous thoughts, see my earlier post Screen time.