While I am young and might be mistaken, there are some differences in how housing figures into people's overall budgets...
I've been told it used to be considered a good rule of thumb that one's housing costs amounted to 25% of their income (I don't remember whether that is post or pre taxes). However, that figure is more like 30-40% for people in many urban markets - so therefore, they have less financial flexibility.
Also, it used to be that you had to have 20% downpayment to get a mortage. Now people are using 100% financing with little or no downpayment and dont have the kind of reserves in case of any financial problems...
Plus, what about rising personal debt levels? That makes people more at risk for not being able to make their mortage payments.
Add in some major national or regional economic problems and that could start a bubble burst
well... just my cheap two cents
