I’m going to post 2 examples, one going your way, one going the opposite way:
#1: A terrible movie adaptation
Queen of the Damned. I had read all of the Vampire Chronicles books up to Memnoch the Devil, and I liked Interview With the Vampire. I bought the soundtrack before watching the movie, and then really wanted to see it. And, Aaliyah was pretty hot. Man, was that movie a travesty. Even as a fan, I was bored. For someone that knew nothing, it had to be a snooze-fest. Ironically, if they had followed “The Vampire Lestat”, rather than cramming two books together, it might have been good. Probably not. (The soundtrack was better than the movie, so something good came out of it.)
#2: Blade Runner
I love Blade Runner. Especially “The Final Cut”. If there is ever a choice of movies, and someone suggests this, I’ll always vote for it. I can always get something new from this movie, whether it’s just soaking in the visual style, the acting, the nuances, the lean script that manages to tell such a great story, the fantastic characters, the Vangelis soundtrack, the open-endedness of the script, everything.
Do Androids Dream of Electric Sheep is a fantastic novel. I love the idea of Mercerism, the realistic way PKD deals with an environment gone to hell, the mood organ, the sadistic androids. It’s as zany as any PKD, but more focused than most of his novels. One of my favorite novels.
I don’t like either one more than the other. The book has a similar setting to the movie, but both follow different themes. I love the action of the movie, and the in-depth philosophy of the book. I love the characters of both.
Anyway, I guess I concede to your point when a pointless movie is made of a novel as a form of cliff-notes, to dumb it down for movie audiences. A movie and a book are different mediums, and a 2 hour movie has to be much tighter than a 400+ page book. For an actor to portray everything with a look of the eyes that three paragraphs can do in internal dialogue in a novel is a pretty incredible thing. And nowhere else can you reach the height of a great soundtrack, acting, and script coming together, in any other medium. So, I think your point that movies are a second-rate medium is very, very, far from the mark.