The fundamental lesson lies in Alan Greenspan's decision a decade ago to bloat the supply of money in the world's largest economy. He did this because he thought - and he should have known better - that this was an opportunity to raise everyone's living standards to the point not where poverty was eliminated, but where most of the people in America had enough to feel relatively prosperous
People seem to forget that the main problem in all of this was banks lending money to people who, to be frank, really shouldn't have been loaned anything. It was driven not by capitalism but by the concept of wealth redistribution and this has been emulated in Britain where virtually everyone had access to cheap credit.
Yes, the bankers got greedy, but greed is a human failing not a failing of capitalism. The fact is that everyone got greedy - including those who really couldn't afford it.
So the next time someone tells you that this is a demonstrable failure of capitalism, point out that the actual cause was a desire to redistribute wealth - and therefore yet another failure of socialism.