Housing is the classic supply/demand market. It is entirely driven by the demand for housing and by the supply and this market is balanced at the point where as Petera says ^ the value of houses will just reflect the amount of money that people can afford to borrow.^
Where she is wrong is in thinking that were she able to 'magically' halve house prices, it would make any difference, because the moment she halved prices so many people would rush into the market to buy all the houses that were now so cheap that prices would return to their higher level with in weeks, if not days.
The housing market will always adjust back to the balancing point. No builder will build a house that costs more to build than they can sell it for, if prices fall too far, they just stop building, this limits supply. If prices go too high or economic or other circumstances means that there are fewer buyers out there than houses, this limits demand, then prices fall, in each case until they reach the balancing point, which is how much people can afford or are prepared to spend each month on housing.
It is not a mortgage market, because even if loans were interest free, or you had to pay cash, prices would be regulated by how large a monthly repayment you could make, or how much you could afford to save each month, to get to the pointwhere you were in the market to buy a house.