Slavery.

2 fundamental things social humans use nearly every day:  literacy of ideas (language) & literacy of actions (money).

We teach just enough of language to spread propaganda, but stop short of teaching enough of it to see past the propaganda.

Much of the propaganda is a narrative about or in service of economics, of which we unsurprisingly teach nothing to students.

The best logical reason for this level of ignorance/ineptitude to persist for so long past the Enlightenment Era where mass literacy was sparked is to preserve the institution of slavery, an owning class & a working class, with workers who truly honestly believe monopoly credits are a fair trade for their life's work.