True, some of it just random. But some is not. There were reasons why that boom was unsustainable, and they weren't hidden. One can argue nobody knew how and when exactly the break will happen - maybe now, maybe in a week, maybe in 5 years - but it's not possible that everybody gets 0% no doc loans on any house and it continues forever. To figure out the intricacies of why it happened and how it broke, you need a lot of knowledge. To know it's not normal and there would be a point where it has to change - you don't need that much, and many people did. Discounting them as random cranks is not right.