Here is an interesting observation from Zingales:
"The real effect of Gramm-Leach-Bliley was political, not directly economic. Under the old regime, commercial banks, investment banks, and insurance companies had different agendas, and so their lobbying efforts tended to offset one another. But after the restrictions were lifted, the interests of all the major players in the financial industry became aligned, giving the industry disproportionate power in shaping the political agenda."
hat tip: Arnold Kling