Reading is a technology for perspective-taking. When someone else's thoughts are in your head, you are observing the world from that person's vantage point.
Babies are born with the instinct to speak, the way spiders are born with the instinct to spin webs. You don't need to train babies to speak; they just do. But reading is different.
Education is a technology that tries to make up for what the human mind is innately bad at. Children don't have to go to school to learn how to walk, talk, recognize objects, or remember the personalities of their friends, even though these tasks are much harder than reading, adding, or remembering dates in history. They do have to go to school to learn written language, arithmetic, and science, because those bodies of knowledge and skill were invented too recently for any species-wide knack for them to have evolved.