This post from mediate.com is a must read:
Carroll Straus June 1999/January2011
“I am the great and powerful Oz...” said the little man behind the screen. Oops! The curtain slipped, and it was--- a mere man! Oh, what a dreadful discovery! How much happier Dorothy was when she thought the wizard had the powers he pretended to have!
The moral of that tale, as we all know, is that although the resources Dorothy sought were not to be granted by the wizard’s awesome power, they were... within her.