The pace of advancement in human civilization, expecially in science and technology (and all the conveniences and economic multipliers that have resulted) was very slow until literacy became widespread.
Before most people could read, you would learn a trade from your father or as an apprentice. Knowledge was handed down but you pretty much learned "the way it has always been done" and improvements were slow.
Once we all could learn from books and publish our discoveries, the spread of knowledge and the pace of advancement exploded. We went from farming with animal labor to walking on the moon in under a century.
Before most people could read, you would learn a trade from your father or as an apprentice. Knowledge was handed down but you pretty much learned "the way it has always been done" and improvements were slow.
Once we all could learn from books and publish our discoveries, the spread of knowledge and the pace of advancement exploded. We went from farming with animal labor to walking on the moon in under a century.