The main reason I suppose why I don’t necessarily agree with you is I was thinking about more kids, than just Canadian (western) kids, which I should clarified. In the 17yrs of my life I have lived in 4 countries and the problem with people glued to their screens is largely a more western problem.
I think that a major contributor to people being on their phones so much is because of how individualistic western culture is. People are on their phones all the time to distract themselves from the fact that they probably don’t have any deep friendships and are extremely lonely.
I most of the countries I lived in were in Africa, and yes people there don’t really have phones due to the lack of infrastructure and availability, but I still think people there wouldn't be so caught up with their phones simply because they think differently from the average westerner. They value community and family much much more than it is valued in western culture.
An interesting thing to note is how western of an idea social media is, you are basically saying to everyone look at me, look at what I am doing, if you think about it there is nothing social about it it is all about yourself.
Sorry for the long tangent, but the point is this whole phone, mental health crisis is largely a developed western world problem.