I think the breeze got it right: If banks/lender/brokers qualified buyers of homes and were willing to lend money accordingly than that in fact means the buyers were qualified. If there was a default to occur, the bank/lender can hardly be blameless since they were willing to provide the purchase money.
Thus, if am the banker and have money that I am lending I would be far more careful in making sure I get the money paid back than the borrower, who can simply walk from the home.
However, what skewed this arrangement was that the banker could easily resell the loan to the financial wizards of Wall Street. Thus, there were enormous incentives for the bankers to sell or refi loans with little consequence they were playing with their own money or be stuck with the bad loans and would lose since they could repackage the loans to other buyers.
