Your comments re: parents setting limits are so true. But It can be difficult to manage all children's activities , even when parents try to set boundaries.
It makes me think of, when the movie ratings started in 1968- to help parents figure out what was appropriate for kids to watch.
It would be great – if some standard was set – by who (I’m not sure), so that schools/parents, etc had common knowledge about daily healthy screen time, how often to take breaks etc, to help create a harm reduction approach to using tech.