I know we all as a family have way too much screen time but that's simply who we are. Our TV is always on except for when we're doing school work (homeschool) or when we're reading. We would enforce stricter rules if the boys really didn't want to do anything else but they are both really good about dropping the screen and playing with toys or doing something creative. And I LOVE having iPad for homeschooling. We have Kindle fire and Nook for fun and iPad for learning. Our kids don't have the patients to learn from people, including me, but they instantly absorb information that comes to them from the screen. I was the same when I was a child. I couldn't stand people trying to explain things to me. I had to figure everything out on my own. And all this technology gives them a chance to do just that and beyond.
That said, we do have friends whose kids will just sit in front of the TV or computer and get this blank stare on their face and they are in trans. They don't seem to be learning anything, they are just there to watch. If that was the case with our boys, we'd just turn the screens off. At that point I'd find it useless and even harmful.