Many of these derivative instruments are based only on the promise that somebody, somewhere will pay a future stream of income. And if that risk goes outside the bounds of the models assumed in devising and trading these things, you get system lock up.
Good questions: What is the source of money for these global financial markets? Central banks appear to be just the primer to leverage their money values and trading volumes. And is the global system just creating its own source of money by multiple-leveraging the collateral on which money generation was once based? In other words, does expansionary exuberance mixed with loop-back complexity create more bloat from its own bloat?