I did begin a story placed about 100 years after the Downfall [of Sauron], but it proved both sinister and depressing. … I could have written a ‘thriller’ about the plot [to overthrow Gondor] and its discovery and overthrow—but it would have been just that. Not worth doing.
Authors often fall victim to their own success. They create something beautiful: a world that stands on its own. A work that neatly wraps up its loose ends. A satisfying ending to a fantastic story. But once this imaginary world grows popular, the “imagineer” faces pressure from all sides. Agents lick their lips. Filmmakers chomp at the bit. Fans froth at the mouth. They all want more, artistic integrity be damned
Many fine writers can’t resist. They revisit (and dilute) their masterworks. For example, after the mammoth success of her Harry Potter franchise, J.K. Rowling (admirably) resisted the clamor for further sequels for years. Eventually, though, she gave in—then gave in again.
Let’s be glad that Tolkien had better sense.