Take Dick for example: whether his writing deals with "the highest kind of truth" is not important to me. I've read just about everything he's written because I enjoy his writing.
I think this is equally true for Dostoevsky, Conrad, and other acclaimed writers. When I read those authors, I have an emotional reaction. It's not research. I didn't come away from Crime and Punishment with a better understanding of why people commit murder. I don't understand "nautical psychology" any better for having read The Shadow Line. I was moved by those novels. I'd say that makes them entertainment.
I don't think acclaimed literature belongs in a different category than teenage supernatural romance. Twilight elicit an emotional response from its audience just like Ubik does. The emotions, technique, and the audience could hardly be more different, but I see no reason that one of those novels should be categorized as "base entertainment" and the other as "high art". They're both entertainment.
Some literature may contain a thesis but, in my opinion, it mostly doesn't. If someone has to "study" a novel to "get the point" then that novel has failed, at least with regard to that reader.
Just my opinion.
More on topic: I enjoy Roberto Bolano's thoughts on Philip K. Dick: http://www.electriccereal.com/roberto-bolano-on-philip-k-dic...