In the end, the company still employ's approximately "x" number of people -- laying off the children and replacing them with older teens gives the same level of employment, more or less.

Some people are then unemployed, and some people gain employment. Neutral outcome there, except fewer children are being exploited by this one company.

Doing nothing (head in the sand) doesn't lead to change, and without change there'll always be this issue.

Cheers