What Caused The Financial Crisis?

From James K. Galbraith: "There Is No Return To Self-Sustaining Growth" by Lars Schall:

The principal cause of the crisis was the dismantling of the system of regulation and supervision in the financial sector which had for much of the post-war period kept the most dangerous elements of that sector in check. In the absence of an appropriate system of effective supervision and regulation, what happens is that the actors in the system, who are intent upon taking the greatest degree of risk — including actors who are intent upon using fraudulent methods to increase their returns — come to dominate parts of the system. As they do that, the general methods of assessing performance in the market, specifically stock-market valuations, become counter-productive. That is to say, they invariably reward the worst actors, while they force more traditional actors, who are still respecting the old norms of conduct, into a competitively disadvantaged position. Thus the bad actors, the fraudulent actors, and the speculative extremists quickly take over.