Movies: "The Hitchhiker's Guide.."

Why are the TV ads for "The Hitchhiker's Guide To The Galaxy" so bland? It looks like any other space adventure film. They've now added a little bit of Sam Rockwell but there's no hint that this is supposed to be an intelligent, whimsical comedy. Typical Hollywood - prune away the very aspect that makes a project worth making for fear of frightening off the masses. (The movie trailers are much better, particularly #3 on the website.)