For that to happen people would have to agree with the basic fact that "teenagers wanting to watch porn is normal", which generally doesn't go well. But ultimately it's such a touchy topic that the people honestly wishing to protect their children cannot even do it effectively. Some don't know how to handle it, many just ignore the matter altogether.

Then we end up with these moral panic-driven measures that at best help no one, or, more cynically, enable the erosion of people's rights and unjustified persecution.