It's weird how they focused on A Scanner Darkly, I thought Ubik was more prescient in the small part of the plot that corporations run the world and advertising for them is ubiquitous.
One of them is a movie and the other one isn't (although searching IMDB tells me that an Ubik movie is in development - yay!). You can't expert journalists to read books now can you?
Going off the main topic, I was reading one of PKD's short stories, Second Variety, and I thought I knew how it was going to end because it was made into a movie I had seen, and it did turn out as expected but the movie that was made from this short story (I have watched it as well) was not the first one that came to mind.