I believe that the push to educate all young Americans was a push to expand the power of the middle social classes at the expense of the typically uneducated lower classes. Success in this endeavor is measured by the proliferation of middle class norms and tastes, not necessarily the expansion of middle class economic prosperity.

This is also why so many Americans talk about being “middle class”, even if they fall well outside the middle of the economic range, because they’re talking about the middle social class(es), not the middle economic class.