WHAT you learn at school are facts, known facts.
Your job at school is to accumulate and remember facts. The more you can remember, the better you do. Those who fail at school are not interested in facts or maybe the facts are not put to them in a way they find interensting.
Some people simply dont have a great faculty for memory. It doesnt mean they are stupid. it means their imagination hasnt been fired up by academic tuition. People who are conventionally clever get jobs on their qualifications (the past), not on their desire to succesed (the future).
Very simply, they get overtaken by those who contiunally strive to be better than they are.
As long as the goal is there, there is no limit to anyone’s achievement.