Humans receive an enormous amount of training data in forms not currently available to LLMs.
If you locked baby Einstein in a room with the collected works of humanity and left him there for a lifetime, I doubt he'd have even learnt to read on his own.
Of course not, not any more than he’d learn to program a computer on his own.
Reading and writing are not natural skills. They are a technology that was invented by humans and they must be taught in some capacity. As we learn to read and write, parts of our brain related to language and other skills (which we do possess naturally) are co-opted to enable reading and writing, an unnatural skill.
Intelligence and language, however, are natural human abilities that we have evolved, likely over millions of years. Any parent will tell you this is obvious. It’s amazing how much children are able to infer and learn on their own.