Allow me to remind you the manner in which child labor was outlawed:

Industrialization progressed to a point where it was no longer economically viable except in a few tiny niches. It was then outlawed, to much back patting.

Sure, some people would probably use it if it was viable, but don't pretend like it was some great accomplishment to outlaw it. It was basically a case of writing law after the market had made a decision.