A question that friends of mine could not answer regarding the housing bubble was why weren't the banks in question so avariciously predatory before 2000? The typical answer was that a new generation of bankers had spontaneously decided to throw out decades of best practices in favor of taking short term profits and leaving the mess to be cleaned up after they took their severance packages.
Those fiends definitely existed (looking at you Countrywide). What most people forget, however, is that there was a push on the lending industry by the government to overthrow the decades of lending practices in favor of achieving social justice. An interagency government task force was established in 1994 to address the perceived racism in lending practices that resulted in greater rates of African and Hispanic Americans being turned down for mortgages. Check it out for yourself.