If you read older versions of common fairy tales, they were often darker and more adult. They were made more kid friendly at some point, because children cannot always determine fact from fantasy, as Tolkien would argue. However, they do want something rooted in reality that didn’t have to be all cutesie. Tolkien’s first book, The Hobbit would attempt this. He was concerned about some of its more darker moments, but witness its success, and depth that exceeds what often passes for “children” books. And so Tolkien, and later C.S. Lewis with The Chronicles of Narnia, would bring fairy tales out of the nursery and gave something that would drive a child’s imagination and be sophisticated enough for an adult. Then, Lord of the Rings would take this further, bringing fantasy to maturity.
Bradley J. Birzer writes in J.R.R. Tolkien’s Sanctifying Myth, that fantasy — or fairy stories as Tolkien would often call them — is worth “the effort of entering” in spite of “its many perils and the great possibilities of misunderstanding” because:
…fairy stories illuminate the vast inheritance our ancestors have bequeathed to us…[they] give us a new sense of wonder about things we have taken for granted or which have become commonplace…[and] provide humans with a means to escape the darkness, conformity, and mechanization of modernity…this is not the same thing as escaping from reality. We still deal with life and death, comfort and discomfort. We merely escape progressivism and the progressive dream, which reduces all of complex reality to a mere shadow of creation’s true wonders
Middle-Earth was much more than elves, orcs and trolls. Of course, what do you expect from an author who was an Oxford scholar who created an entire history, new languages and new races for his mythos? And those things were not even what made it great.
The very human stories were.