The numbers don’t lie: The housing crisis is not caused by a supply shortage
(www.policyalternatives.ca)
Financialization occurs irrespective of supply and demand by making more credit available. It's literally injecting money into that specific market. Once people see prices rising, the rising prices become part of the product - people buy as much housing as they can as an investment vehicle. It's like the effect of people buying a stock because it goes up. Everyone I know has either bought additional property as investment or wanted to but couldn't afford it.