you forget a couple of key factors:
- Houses are most famililes single largest investment.
- If your neighbor's house falls in value by 25% because of foreclosure it also pulls down YOUR house value and YOUR retirement investment. This makes you both less able to and less willing to spend
- Very few people can afford to buy houses without the help of a bank
- Banks ability to lend are dependent on having "good loans" on their books. When they have loans they expect to go bad, or which they cannot tell are good or bad, they LEGALLY have to set aside cash to cover those bad loans. And that is cash they cannot lend
- It COSTS roughly $75/sqft to build a moderate income home. Plus land cost. That means the average new home is going to cost $200+ (2000sqft ==> $150k+$50k+ for land) and this generates some $1 Trillion worth of jobs
#1, #2, #5 essentially cripples the economy if you let housing prices plummet BELOW fair value
#3 and #4 demonstrates that houses are only "overpriced" in your opinion. The current downturn in values is being driven more by a lack of lending than by the inherent "overpricing" of houses.
As for the "market will take care of itself" - that all depends on what you mean by "take care of itself". Will it reach an equilibrium? Sure. But is that equilibrium going to be one that helps expand or contract the overall economy? That is a completely different question.
We know from history, that unregulated markets get distorted in their own ways and suffer from more dramatic booms and busts. And we also know that over time, big Boom/bust cycles result in LESS NET GROWTH.