Greed given a free rein
With respect I feel one must look at a system of governance that provided free rein for these same financial sectors to indulge and exploit natural human greed.
Neither the banks nor their customers would have created such a financial mess if the various governments of recent years and their advisers — mainly senior civil servants — had not provided a regulatory structure so loose that greed could run rampant, and if they had not refrained from monitoring the effects of those regulations.