All these theories are great for prices to always rise and I hope they are true but they all sort of go out the window when you look at the USA for example.
Sigh ... here we go again as this has been done to death on SS ... you cannot compare the USA with Australia.
Three reasons off the top of my head ...
Massive tracts of land were being developed, and houses built, with no buyers. In Australia a developer has to sell off the plan nearly 100% (in current market) before the bank will lend to build.
Banks in the USA were lending money for property to people with no jobs, no assets, no money, no deposit. In Australia you currently need around 10-20% deposit, prove that you have a sustainable income and that can comfortably pay the loan at 2% higher interest rate than current.
Many of the States in the worst default prediciment (asides from Florida) has non-recouse loans. This means you can hand the keys back to the bank and the bank cannot chase you for any money. In Australia there is no such thing. The bank will not hesitate to send you bankrupt if required.
Now - back on topic.