I would love to live in a society in which teenagers and young adults spent more time apprenticing and less time in formal schools. But in the current economy,

I would love to live in a society in which teenagers and young adults spent more time apprenticing and less time in formal schools. But in the current economy, I wonder how practical it is. Even if the apprentice works for free, training the apprentice is a cost borne by the master. Masters have to risk seeing their apprentices go off and work for someone else (or, heck, work in a totally different field) and apprentices have to risk discovering that they were kept so busy with menial work that they didn't actually learn anything.