To the extent that art deals with deep issues of critical importance to humanity, it at least strives to rise above the mass of "pure entertainment" which does not strive for anything more than entertaining and distracting its audience from just such serious contemplation. To the extent said art succeeds in what it tries to accomplish, and does so in a profound, engaging, and unforgettable way, it is great.
With the sole exception of an added vampire/werewolf hunk you nailed it. The subject matter though is less problematic than the really abysmal writing. PKD didn’t always have the best writing style, but made up for it with content. Twilight is derivative content delivered in appalling fashion.