^Yep. Writers are the power in TV, but are virtually powerless in feature films. In films, writers are seen as merely hired contractors whose job is to put the director's ideas onto paper. If a writer doesn't do what the director wants, the director will bring in a new writer who's better at following instructions, or will hire a dozen writers to write a dozen scripts and then stitch together a shooting script out of fragments of them all.
Here's a tale that illustrates the relative power of directors and writers in feature films. There was a screenplay making the rounds a few years ago called
Nottingham, about the heroic Sheriff of Nottingham using medieval crime-solving techniques to track down a terrorist band in Sherwood Forest that preyed on innocent rich people. It was an innovative twist on the Robin Hood premise and everyone in Hollywood loved it. But then Ridley Scott got hold of it and had his own very different ideas about what to do with a Robin Hood movie, and in order to achieve his "vision," he hacked away everything that was distinctive and original about the screenplay and replaced it with the ordinary, uninspiring
Robin Hood film that came out and quickly flopped earlier this year. (Or so I gather; I didn't see it, because it didn't look interesting.)
That's why you don't blame the writer when a movie is bad. Because writers have no power to get their way in the film industry, while directors have effectively absolute power.
The main exception is when you get writers into positions of authority like producer or director. This is particularly true with writer-producers or writer-directors from television who go into movies. This is why
Serenity was true to Joss Whedon's vision whereas the original
Buffy the Vampire Slayer was such a bastardization of it: because he got to direct
Serenity. It's also why Orci & Kurtzman's
Star Trek script is so much better and more coherent than their
Transformers: Revenge of the Fallen script: because they were producers on Trek and were working with a director and executive producers who came from TV and were used to respecting writers' input, whereas on RotF, they were just hired help brought in late in the process to slap some dialogue in between the big action set pieces that Michael Bay had already put together on his own. Granted, that's an extreme case because the writers' strike was on for the first part of that process, but it shows that the writers are less central to the operation in that franchise.