Wow 2 years of the last 10.
Yup, they worked all right. 
What are you talking about? They worked until the mortgage bubble burst in 2007.
OK, so why did the mortgage bubble stop them from working WBC?
You're asking me why a financial market bubble crash tanked the economy? Is that the question?
My question would be: why do you think anything that creates bubbles BEFORE they burst actually works? If it creates bubbles, it's not working.
