There seems to be this hangup with moviewatchers and metaphor. By which I mean this: in a book, you can have an extended metaphor that runs throughout the story (most good books arguably have this), but this metaphor doesn't actually influence the story. Now, of course you can have some books here and there in which it does influence the story, but for the most part the two are separate.

So I have to roll my eyes when I see people insisting that it has to [not] be a dream, because <insert extended metaphor here>. Yes, there are multiple layers, but they don't necessarily influence the other. Basing an interpretation entirely on metaphor is shoddy analysis.