I agree with your premise, but this example I strongly disagree with:
> You might as well be saying that you can just explain to children why they should eat their vegetables and rely on them to be rational actors.
YES! Explain to them, and trust them. They might not do exactly as you wish for them, but I'll bet you don't do exactly as you wish for yourself either. The children need your trust and they must learn how to navigate this world by themselves, with parents providing guidance and only taking the hard stance (but still explaining and discussing!) when safety is concerned. Also, lead by example. If you eat vegetables then children are likely to eat them too. The children are not stupid, they just don't have enough experience yet. Which you gain by trying (and failing), not by listening.