I think the article writer misses how much of it is really about The Silmarillion, rather than about Lord of the Rings. Tolkien put a lot of work into First Age geography, an entire (interminable, excruciating) chapter of The Silmarillion. Very little of it would be familiar to viewers of the films, and a lot of it opaque even to readers just of LotR.
Tolkien himself didnt “write” the Silmarillion the way people might assume. He spent decades writing and iterating on mythology, world building, creating languages. He had multiple versions of many stories and ideas, many drafts in various states, but he never pulled it all together into a single book or officially canon narrative.
After his death his son Christopher took on that monumental task, with great care and understanding of his father’s work. Combing through who knows how many mountains of notes, unfinished stories, and contradictions to create what we know as the Silmarillion. Tolkien himself often said of things in the LOTR canon “I don’t know” or something loke “I havent translated/uncovered that yet”. He looked at it all as if he was a literary archaeologist, translating passed down texts. So with that came lots of uncertainty and hearsay. The fact that his son tackled that, maintained that mystique, and created the Silmarillion is really exciting and lucky in my opinion. Good kid, I guess!