[apta]

> During and after the economic collapse of 2007-2009 I wondered who was at fault; who to blame

Sometimes it is possible to at least narrow things down to an underlying inherent instability. In the case of your example, a huge underlying cause is an economic system based on debt (backed by interest and usurious transactions). It's for a reason that usury/interest is banned in Islam, Christianity, and Judaism for example. It's a parasitic practice that makes the economy fundamentally unstable. This includes dangerous practices such as selling debt for debt (again part of the same crisis), and things like stock shorting (which, interestingly enough was also banned during the crisis, at least for some critical company stocks).