Two years on, what do we know about the global financial crisis? We still lack a conclusive theory, but we know a lot more than we did in August 2007. We know, for example, that simple monocausal explanations are at best insufficient and most likely paranoid and lazy. If you still blame Alan Greenspan, former chairman of the Federal Reserve, or central bankers in general, you have not got it.
Nor can you explain it by “soft” factors such as greed and bonus payments. These played a role but none can serve as an adequate explanation of why the crisis broke out when it did, since they had been present for many years.
My own gut feeling: this has been a crisis of economic policy first and foremost. The financial crisis was necessary for the economic crisis to occur but it was not sufficient on its own. Each depended on the other.