The reason there are these movies that are adapted from books and don’t do well at the box office is that there are many people who haven’t read those books. Even though it’s reasonable that production houses see movies as standalone creative products, separate from the books, it’s the existence of an audience for either that’s driving the production itself.
The point is to capitalize on the potential ‘popular culture value’ of the book being adapted. And when a movie adapted from a book bombs, I think it’s because someone misjudged the size of the audience for it. The movie is subsequently forgotten, leaving no capitalizable trail of its own.
The reason I’m complaining is that I love such movies – which people think don’t do much but I think they do a lot for me. When I read books, I don’t focus on everything the book throws at me. As the plot develops, I am generally able to pick up on what’s relevant and what’s not, leaving the characters to play out in my mind as if located nowhere in particular but simply existing of/by themselves.
Now, when this ‘dud’ of a movie comes along, it fills up these spaces nicely, colors inside the plot-wise irrelevant boundaries. That’s why if there had been more people who’d read the book than those who hadn’t, the movie might’ve been appreciated for what it really was: not a creative standalone but a product crafted only to capitalize on existing emotions, not create a new one.
Most recently, Atlas Shrugged Part I did this well. The actors didn’t try to put up a performance of their own, abiding quite nicely by the narrative railroad set up by the book.
The same can be said of the Lord of the Rings trilogy, but Tolkien left little to the imagination, not that that’s a problem. If anything, the movie was always only threatening to fall short (like The Hobbit Part I did), the difference being that The Hobbit left a detestable Narnia-like episode firmly lodged in my mind. That’s also why I’d rather a movie fall short if it can’t land on just the right spot, and if it can fall short, why wouldn’t it be a hit?