I don't understand how people fail to understand how public policy works. You can tell people to do something and they may or may not ignore you depending on how you say it, and what incentives and penalties you provide.
Being a parent or a teacher puts you in a position of fighting multi-billion dollar corporate interests that are trying to capture your kids' attention. It's also fighting their very successful advertising campaigns that makes kids, just like adults, feel FOMO for not having the latest gadgets, or access to the same social media outlets as their peers.
Any public policy trying to counter this needs some weight behind it, and a strong consensus as to what we value as normative behavior in society.