You feel that way because that's exactly how it happened. Tolkien was a linguist first and foremost, and he created the languages used in the books for fun. Then he created the worlds and the lore for those places to exist. And only after all of that did he actually write stories set in these worlds and the languages in them.
It's genuinely magic to read. And I really don't feel like anyone has matched his authenticity in the fantasy genre.
I love C.S. Lewis, but the Chronicles feels very artificial. A new venue to preach his religious motives. Fun, and well done for sure. But not the same.
I also love the Steven R. Donaldson series The Chronicles of Thomas Covenant. It's a moral journey just as LoTR and Narnia are, but it's a deeply personal struggle for a guy trying to manage his own mix of character successes and failures, rather than epic characters who each represent one idealized version of a human trait.
But as much as I love that series as well, I feel very much like the world was created for the story, and not at all that the world was created simply to create a world, and the story was created for it.
Tolkien really did it perfectly. I don't know that he ever intended to do what he did. It could be argued that it's not really correct to call him a master at his (or any) craft because he wasn't trying to do anything like what he did. There's a certain accidental quality to it. Which is perhaps what makes it so compelling.