Depression Ahead?

From Steven Gjerstad and Vernon L Smith in the Wall Street Journal:
The events of the past 10 years have an eerie similarity to the period leading up to the Great Depression. Total mortgage debt outstanding increased from $9.35 billion in 1920 to $29.44 billion in 1929. In 1920, residential mortgage debt was 10.2% of household wealth; by 1929, it was 27.2% of household wealth.
The Great Depression has been attributed to excessive speculation on Wall Street, especially between the spring of 1927 and the fall of 1929. Had the difficulties of the banking system been caused by losses on brokers' loans for margin purchases in 1929, the results should have been felt in the banks immediately after the stock market crash. But the banking system did not show serious strains until the fall of 1930. . . .
The causes of the Great Depression need more study, but the claims that losses on stock-market speculation and a monetary contraction caused the decline of the banking system both seem inadequate. It appears that both the Great Depression and the current crisis had their origins in excessive consumer debt -- especially mortgage debt -- that was transmitted into the financial sector during a sharp downturn. . . .
Why does one crash cause minimal damage to the financial system, so that the economy can pick itself up quickly, while another crash leaves a devastated financial sector in the wreckage? The hypothesis we propose is that a financial crisis that originates in consumer debt, especially consumer debt concentrated at the low end of the wealth and income distribution, can be transmitted quickly and forcefully into the financial system. It appears that we're witnessing the second great consumer debt crash, the end of a massive consumption binge.