The only thing I would question is the claim that the Great Depression wasn’t related to a credit bubble. There was sharply rising debt and increased wealth disparity just before the Depression. Just like we have now.
With this dramatic increase in the instalment selling of automobiles came the expansion of this technique into the markets for other major durable goods. According to credit expert Rolf Nugent, the success of automobile instalment plans “tended to remove the stigma which instalment selling had acquired at the hands of low-grade instalment merchants in the 1890s.”20 In fact, credit was used in the purchases of up to 90% of major durable goods by the end of the 1920s.21 Average purchases of major durable goods rose from 3.7% of disposable income between 1898 and 1916 to 7.2% between 1922 and 1929. Accompanying this rise in purchases of durables was a drop in the personal savings rate, from 6.4% of disposable income in the former period to 3.8% in the latter.22
IMHO, all depressions occur when the greatest number of people have the greatest amount of debt, and the wealth disparity is the greatest (tends to happen concurrently because credit shifts money away from the working class/labor to the capitalists/lenders).
Basically, all the future demand has been exhausted (because everyone brings their purchases forward when using credit, and they now have to use current/future income to service that debt), which leads to deflation as the debt is destroyed via rolling bankruptcies and foreclosures.
