I know, 20 year rule and all, but I'm looking for sources about the changing policies towards mortgages, finance and homeownership since the 1950s, or at least the 70s. The 2008 crisis might be very recent, but it has roots going back decades, so I believe I can still post here, plus I trust this sub more than AskSocialScience.
The sociologist Mark Mizruchi has tried to analyse the crisis in historical terms; however, his papers do not focus on the financial products in themselves, but rather on the social background that has enabled their apparition. He argues that the networks of the economic élite have been powerful in America throughout most of the 20th century, but that they have declined in the 70s, thus leading to a lack of coordination between actors. He has published a lot of papers on this theme, but this one, freely available on his website, seems to be an apt summary of his thesis (which I am in no position to criticise constructively).
The Big Short, by Michael Lewis.
It focuses a bit more on the CDS side of the market and a bit on regulation/how the market for housing operated.
It only covers the change of the 2000s in regards to how housing ownership and financing changed. The book assumes mainly that the American housing market (in terms of traditional ownership) went back to the 1950's on the basis of 20% down and fixed mortgages of 15/30 years, with the major change happening in the late 1990s.