The end of The Man in the High Castle consists of:
Julianna Frink visiting Hawthorne Abendsen and asking the Oracle why it wrote The Grasshopper Lies Heavy, the novel-within-a-novel that suggests, contrary to Dick's story, that Germany and Japan lost World War II. The Oracle responds with the Chung Fu hexagram, meaning "Inner Truth", implying that Grasshopper was actually true and the world Julianna and Hawthorne inhabit is fake.
Understanding all that (and I'm assuming I'm interpreting it correctly), what did Dick want the reader to get out of this? What's he saying? My initial thought was that Germany and Japan failed to conquer the US because the arts and culture remained, albeit dimmed, so the new world order they thought they created wasn't really that strong, but that doesn't really make a whole lot of sense to me. Does anyone have a better understanding than me? Am I interpreting the ending wrong?