There is some truth in that answer ; but it is not the whole story . The crisis is not the creation of " greedy bankers " and speculators : it is the result of too much debt , after governments and central banks failed to constrain the credit expansion of the early years of this decade . Bankers then irresponsibly exploited the opportunities afforded by an easy credit regime .

Question: Why did the bankers try to exploit the opportunities ?
Answer: The governments put pressure on them to do what they did .They did n't know any better they were just doing what needed to be done .They are bankers and are trying to get money and riches .The market conditions were perfect for them to succeed .