There's an interesting argument developed in this book by this bloke that I'm currently reading, that part of the explanation for the current crisis is labour's loss of power. The shift in power between... err... labour and capital has allowed business to increase profit ratios (not just profit levels), particularly by off-shoring jobs. However the declining share of income accruing to working people in countries like the US & UK would have had an impact on demand, so governments allowed the explosion of debt to counteract this.
Dunno to what extent I buy this, especially as I still see the labour/capital divide as a bit of a arbitrary one. But it's interesting that a book on the credit crisis argues that the decline of organised labour is a contributory factor. I think I might go back and re-read Capitalism Unleashed.