I thought of the Silmarillion as a collection of ideas rather than complete stories per se. It’s the kind of stuff I write when I’m doing the backstory. Doesn’t mean it isn’t brilliant or worth the read, but I am sure it contributes to its lack of popular appeal. The vocabulary is also troublesome, yes, and it’s a lot of “tell, not show,” which is exactly the opposite of what modern experts tell you to do when writing a novel. All the description also slows the story down immensely. I still think any true fan of literature should read it, however! It’s probably one of the best examples of world building in existence.