In this interview Warren Buffett repeatedly cites the financial crisis as beginning in September of 2008 and gaining momentum in 2009. Framing the great financial crisis in this period ignores the root cause of the great financial crisis. The root cause of the financial crisis was the collapse of the housing bubble. Single family home prices and the mortgages backing home financing began a rapid and fairly constant decline in March of 2006. The significant loss of value in these two major (related) asset classes - single family homes and mortgages - translated, by September 2008, into the broader banking disaster due to the foreclosure crisis and because banks had been trading financial derivatives and interest rate swaps which were based on single family home values and mortgage values.
Any discussion of the great financial crisis should begin with the root cause of the crisis. That is, such discussions should include information about how cheap-and-easy single family home financing arrangements fueled demand for homes, which fueled rapidly escalating home prices, which led to the ill-fated single family home price bubble.