You want to know how simple the solution is? Prevent the Banks from being in the securities business where they can defraud the world markets out of 55T in non existent CDO's. Prevent them from building houses with dummy construction companies and then offer no security loans to sell the houses. And then sell the loans to you.
Prevent them from being in the Insurance business so that they can offer default swaps which are really insurance contracts to 40 times their net worth.
What is left is then to use the money to loan real customers.
That is glass-Steagall. This has all happened before.
An economist I read says that he will believe there is a real credit crunch when his eleven year-old son quits getting credit card solicitations. In my own case I was hoping that the volume of them would drop away and that has not yet happened. Also I do residential real estate in my practice and at the lower end folks (read a lot of young folks) are getting mortgages. I could be wrong but my experience is saying maybe the economist has a point.