The malfeasance of the banks, credit rating agencies, etc., etc, certainly played their part, mostly by turning the economy into a vast Ponzi scheme. But even if the strictest regulations are enforced, an immiserated working class cannot sustain a growing economy.
That's why people keep comparing Obama to FDR, because the only way out is thorugh New Deal, trickle-up job creation schemes and vast social subsidies for the poor rather than the rich.
Joanna