I would argue that the following Einstein quote does a good job of explaining, to a large extent, why that was.
Reading, after a certain age, diverts the mind too much from its creative pursuits. Any man who reads too much and uses his own brain too little falls into lazy habits of thinking.
If you read too much and think too little, your inputs exceed your outputs. The solution:
- When you learn something, teach it.
- When something puzzles you, try to solve the puzzle.
- Give more than you take.