I'm going to gently suggest that the proliferation of screens, the proliferation of choice, the proliferation of personalization, in and of themselves, demonstrates that the principles of the free market place of ideas is well understood. The kids just choose ideas that perhaps we would not choose. (Or in most cases, ideas that we would definitely not choose.) But this is the essence of the free market of ideas that you subscribe to. That children are not interested in the ideas that we are interested in, does not mean that we need to go and make sure they consume our ideas instead. That's kind of the opposite of a free market.

So kids live in a free market, and they generally choose things we, as parents, don't like. This doesn't, always, make the kids wrong. And it doesn't mean that they are in need of our guidance to see things "correctly". (Which invariably seems to mean, "You're wrong kid, this is what you should believe." And then we wonder why they call us hypocrites when we at the same time talk about a "free market of ideas".)