The risk of not lending the banks out is a depression where the currency / global economy may have lost more value. Example: The gov only made 8.5%, but if the

The risk of not lending the banks out is a depression where the currency / global economy may have lost more value. Example: The gov only made 8.5%, but if the US costs have increased 16% over the same period (because of a depression), the overall return is more like 24.5%, ignoring the additional costs of a depression.