An Unexpected Story
Virtually everyone who's ever read The Silmarillion agrees that it is impossible to put on film as a coherent work. It spans thousands of years and a vast roster of characters, yet there's no one plot to link everything together. It's not even a novel; it's a history, detailing the formation of the Earth and everything in it leading up to the events of Tolkien's better-known works.
That said, it references loads of stories, such as the fall of big baddie Morgoth — the Lucifer of Tolkien's universe, and precursor to Sauron — and his attempts to seize power and destroy everything good in the world. Morgoth appears throughout the entire book, making him the closest thing The Silmarillion has to a main character. The majority of his story is wrapped up in his attempts to acquire three magic jewels called Silmarils, and the wars he waged against Elves, Men, and the Valar (higher beings of great power who collectively created Earth) for possession of them.
Then there's the story of Beren and Luthien. You may remember the scene in The Fellowship of the Ring where Frodo awakens at night to listen to Aragorn sing a song about these two lovers. Beren was a man, Luthien was an elf (sound familiar?), and their star-crossed romance is genuinely epic in and of itself.
The book's greatest hero is probably Hurin, a legendary champion of men — whose story Christopher Tolkien would later expand upon in the standalone novel, The Children of Hurin — and the curse placed on his family by Morgoth after Hurin's many exploits.
There's much, much more contained within the pages of The Silmarillion; this barely scratches the surface. Anyone attempting to turn the entire history of Middle-earth into a series of movies would be undertaking an unimaginably huge commitment.
But with so much material to draw from, why not break things up by individual stories and make movies out of them, one at a time? There's probably enough story in the conflict between Morgoth and the Valar for an entire trilogy. Beren and Luthien's story would make a perfect standalone flick. Countless other tales in the book would work as epic fantasy films, too. And there's no doubt Warner Bros. would love to keep churning out money-making movies set in Middle-earth for years to come.
A Snowball's Chance...?
So what's standing in the way of The Silmarillion's many stories coming to a theater near you? Christopher Tolkien. At this point, it would take an act of God to convince the son of J.R.R. to sell the film rights to any of his father's remaining works.
However... There's still one more wrinkle to this twisted tale.
Christopher Tolkien is in his 90s. Forgive the insensitivity, but if we're being purely pragmatic about things, it's impossible to ignore that he's not going to live forever. Whenever Christopher shrugs off this mortal coil, someone new will be needed to take over the Tolkien Estate — and it's possible that that someone may have more tolerant views of Hollywood and the film industry.
Enter Simon Tolkien. As Christopher's oldest son, it's logical to assume that he's next in line to inherit the family Estate. And as it happens, Simon Tolkien — already a successful novelist in his own right — is on record as being a strong supporter of Peter Jackson's movies. He sees them as something the Estate should embrace, thanks to the new generation that's discovered the books thanks to the films.
Simon is so vocal about his support, in fact, that a few years back, it led to a schism between him and his father, during which Christopher actually disowned his own son. (If nothing else, that proves just how strong Christopher's feelings are about the sanctity of his father's work).
Fortunately, their story has a happy ending. Christopher and Simon have reportedly had a reconciliation in the years since their falling out. But one has to assume that they've merely "agreed to disagree," as neither of them have changed their views about film adaptations. Could Simon someday be the one to license the film rights to more Tolkien works to a Hollywood studio (presumably Warner Bros.)?
Don't get your hopes up just yet. There are a lot of unknowns in this scenario. There's no law or rule stating that Simon is definitely next in line to take over the Tolkien Estate; Christopher could just as easily choose to entrust its future to another professional employed there, or to one of its Trustees, or a different member of the Tolkien family. There's no way of knowing until it happens. And even if Simon is offered the job of overseeing the Tolkien Estate, who knows if he would even want it?
So if Simon is asked to take over, and if he says yes, then it's conceivable that he might someday loosen the Estate's stranglehold on the film rights to the rest of the Tolkien catalog. But that's a big if, and it's a long way off.
In the meantime, don't expect to see Middle-earth on the big screen again any time soon.