The whole Emerald City set up could be seen as a critique on capitalism - that it is an elaborate confidence trick which requires everyone to view it through, not rose tinted glasses, but green - a colour with a strong association with money in America (greenback = dollar).
And when thinking of that image the phrase sub prime mortgages comes to mind.
Other commentators have read other political philosophies into Baum's work. But one of the things that's striking to me about the book is that the lead character is female. Dorothy is the one who does things, who refuses to accept and has the insight to really see and not just look.
I read that one of the author's aims was to write in the same tradition as Hans Christian Andersen and the Brothers Grimm but without the violence. If nothing else, The Wizard of OZ shows the enduring power of fairy tale and its ability to force us to reflect.
Anyone seen Wicked, the musical or read the book it's based on? Does that have the same resonance? It must have something - it's been a runaway success - and there may be a lesson there for writers lost for a plot:think about a new take on an old fairy tale.