The whole financial thing is just wackadoodle, of course. But it seems to come as such a surprise to everyone. It really is a lot like Andersen's "The Emperor's New Clothes," in which the climax isn't the townsperson pointing out that the emperor is naked, but in the emperor's realization that he MUST continue his promenade. Because, really, everyone knew that we were trading Nothing, just like everyone in the story really knew that the tailors were sewing Nothing.
And many people seem to be looking for someone to blame. Really, the one to blame would be the person who pointed out that the loans were worthless, because the emperor would have been just fine if nobody had pointed out his nakedness.
The other story by which to explain this is "It's a Wonderful Life," the only real contact any true American has with the housing lending industry. "Look, I can't give you your money now. It's in his house and her house..." And even the bailout/injection seems to be a wishful-thinking version of the end of the movie where everyone brings in their cash. "I was saving this money in case I ever gets me a husband." But there, at least, you have a Mr. Potter to dislike. Instead it turns out that we're all Uncle Billy.
Again. Oh, well.