I would have to agree that the GSEs played only a minor role in the housing bubble. As I recall (and I could be wrong), the biggest causes were the securitization of mortgages into MBSes combined with shady underwriting practices. Why bother caring if someone can pay back the loan when you’re just immediately going to sell it into a bundle of toxic waste that you can then sell to someone else.

Was the repeal of Glass-Steagall behind that change in mortgage financing? I’m not sure but the timing seems right since these silly MBS things appeared immediately after.