I watched a docu about Shakespeare today. By age 12 he had a college level education - taught mostly in latin. By age 18, the equivalent of a doctorate. He was not the only student in the class, not the only class in school, not the only school in his parish. So, if children of 500 years ago could absorb knowledge and be able to logically process it, and children of 100 years ago could do the same, it’s not a lack of cognitive ability. Unless the IQ of the attendees has been dumbed down by external factors. Or college has just become another place to goof off and squander borrowed money outside the confines of the parents’ home.
Trying to educate the third world is tough.