I agree entirely with your first point about child labor —banning and/or restricting it severely was an unambiguous good. If you buy Collins’s thesis, then this is one of those times when capital and social morality lined up.
And your second point illustrates exactly what I was saying in the first part of my comment: mandatory education— even of the de facto variety — attempts to paper-over capitalist contradictions, but can’t solve those contradictions. In the situation you eloquently discuss above the contradiction is that one needs a credential to be considered for these “high skill” jobs, but that one takes on more debt and fiscal hardship in order to gain that credential. The real contradiction, of course, is central to capitalism itself (not its educational apparatus): increasing productivity means fewer employees needed to produce…which means fewer people to buy goods and services.
Now I wonder where all those profits from increased productivity have gone? Anyone want to guess?