Picking up where you left off, I do not see how we can blame those who lied to get loans, etc. I am not saying such is the right thing to do, but under normal circumstances, lenders would have never been willing to take folks at their word, make such "risky" loans, etc. The normal mechanisms of capitalism had always kept such to a minimum.
The root enabler of the crisis was the monstrous inflation in the market. It helped to eliminate the risk of these sub-prime (and worse) loans, because it did not matter if the new owners couldn't afford it a year or two down the road. You could take the house back, cover all foreclosure costs, and resell it still at a profit with such insane inflation. Too much money to be made too easily to not predict that the bubble would do as bubbles do, which is make money for everyone ..... until it popped.
So what enabled the inflation at levels we had never seen before ? Too many new buyers. Where did they come from ? Fannie and Freddie underwriting the subprimes starting in larger measure beginning in 1997.
Hate to admit it, but nothing was going to stop the bubble once it got going. Not a politician in the world was going to say "hey wait" and be able to draw much of an audience.
But as George Bush was politician #1, it was his responsibility #1. And all the rest with him.
The repeal of Glass Steagle added to the frenzy, but we were going to have a bubble, and a burst, and 25% of American mortgages underwater regardless. And a recession.