What didn't cause the housing bubble

Via EconLog: Two recent popular scapegoats are not responsible for the housing bubble:

Robert Shiller wrote,

Dramatic home price booms since the late 1990s have been in evidence in Australia, Canada, China, France, India, Ireland, Italy, Korea, Russia, Spain, the United Kingdom, and the United States, among other countries.

He has charts suggesting that the Netherlands and Norway experienced greater booms than the United States. In his book The Subprime Solution, he has a chart that shows London house prices rising faster than prices in Boston.

What makes this a difficult fact is that so many explanations of the house price boom are U.S.-specific. It is hard to argue that the Community Reinvestment Act or the repeal of Glass-Steagall are what account for the home price booms in Norway or Spain.