No, easy mortgages did not cause the 2008 bank failures. Reckless banking caused it. Banks were selling mortgage packages wirh "default optionsc which were essentially derivatives to cover the holder if loans defaulted Banks held these and other options that were vakued in MULTIPLES of the mortgages. When losses due to mortgages begain to increase the banks and other financials institutions tried to settle the losing positions in dericstices any were unable to pay, causing a domino throughout the industry. Note that they are doing it again.