Why should every job provide a 'living wage'? A high school kid working through the summer at an ice cream shop is learning to work, learning responsibility, and getting a little spending money - why would you want to outlaw that?
Anecdotally, I did work as a kid, didn't learn anything useful, did not learn responsibility, a bit of money I didn't really need, and it felt like a waste of time and left a bad taste overall.
I fully believe that in many, possibly most cases, work is beneficial for kids (as long as they're not from poor families in which case there will be too much pressure to overwork, affecting school/homework and taking away whatever little time they have to enjoy childhood).