Ok, this is a weird one. In 2025 I attended "A Night with Francis Ford Coppola and Megalopolis" in Chicago. They screened the film, and then Coppola "lead a discussion about the future". It was a strange evening.
During this discussion, Coppola mentioned a book that he had read in which the core argument was that through out early human history, several major inventions originated from children's play. The two examples Coppola listed from the book were the wheel first being used by children to play games, rather than adults to transport things, and Art in the form of Cave Hands, which children size hands appear along side adult sized hands.
Does this ring any bells for anyone. The book sounds interesting, and I have been meaning to locate it, but I do not believe he ever actually gave a title (his discussion was quite ramble-y).