For years Lord of the Rings was known as the "unfilmable" film. People thought it couldn't possibly be adapted, filmed, and released in a viable manner - let alone become a huge hit. They succeeded beyond anyone's expectations, becoming one of the only trilogies ever to have each film surpass the pervious one's box office numbers. And lets not forget the dozen or so oscars ROTK won.
Have a little faith. While The Dark Tower isn't nearly as hyped or popular as the Harry Potter series, the hype it drums up while a new film is written, filmed, and released would be considerable. Especially if a notable director like JJ Abrams is attached to it.
Plus, the first book - The Gunslinger - has a pretty kick ass title. If that doesn't draw people to the movie, nothing will!
I have to you missed out on Jungleland. It is the ULTIMATE film/Springsteen song to me; it is so epic and heartbreaking ("In the tunnels uptown/the rat's own dream guns him down/as shots echo down them hallways in the night")