[fancifalmanima]

I'm definitely speculating, but I could see banks having a glut of money to loan contributing to the low interest rates that have existed for a while now (thinking of money from a supply/demand perspective). With those lower interest rates leading to more interest in buying homes and pushing up prices (during the subprime crisis, to folks that couldn't necessarily afford it). While you'd also expect a housing construction boom, its certainly plausible that the industry would have to play catch up to demand. (It seems easier to me to hire a realtor to go look at homes than to start or expand a construction business). Zoning/other regulations can also slow down that process. The low interest rates also make larger/more expensive homes more feasible for buyers, due to the fact that a smaller percentage of the monthly payment is interest. I could certainly see ways that the above would lead to an individual having a higher debt load than they otherwise would.