Yes, speculation that prices would keep going up. Remember all of the peak oil discussions and the thought that the last marginal barrel couldn't be pumped to keep up with the last marginal demand?
Yeh, the pundits of the right & the sheep of the financial sector also believed that the price of housing would go up forever.
We both know that when the big boys see the chance to make money from a bubble that they try to create one. Tech stocks. Housing. Oil. Stock market. The price of tea in China.
Bubbles have jack & shit to do with supply & demand but rather everything to do with exploiting perception.
Anybody who wants to know which way the economy is going needs to read these guys, then figure it's going the other way-
http://economicsofcontempt.blogspot.com/2008/07/official-list-of-punditsexperts-who.html