* Debt levels in Australia are worse than in the great depression.
* The income to median property price ratio is at 7 in Australia, but historically it has always snapped back to 3. Incomes are either going to go up massively because of inflation, house prices are going to fall by half, or some combination of the two. Either way, you'll lose by owning a mortgage/house.
* Housing shortages don't prevent big price falls (refer to NZ)
If you claim prices will rise, explain where you think the money is going to come from? For someone to buy your house for more than you paid for it, 1) they have to borrow the money (getting much harder to do) and 2) they have to believe it's a good investment (no one is predicting 10% gains in housing any time soon!). Pick up the AFR folks. Every week there's stories of real estate investors being forced to sell, or choosing to sell so they can make the most of their belief that shares will rally.
Once critical mass is reached, you'll see supply outstrip demand and then you'll all get a lesson in economics 101. Prices are set on supply and demand only (housing shortage doesn't increase demand because it doesn't mean that more people can _afford_ to buy a house).
