I imagine it's hard to sell the thing the anchor around your neck which is dragging you to your death. Financial derivatives, they were gambling. Not really, they buy securities and then buy a counter investment in a derivative so that they win either way the market goes. That's the theory. The derivatives have massive downside though so if you get it wrong in your math models, you are shafted. I'm not sure what they got wrong but another such crisis was the Long Term Capital Management one in the 1990s. They didn't foresee the crisis in Asia and were heavily invested in derivatives based there. They almost tool out all of Wall Street and had to be bailed out by the fed (by us, actually).
Don't worry, convolutional neural networks have it all figured out.