penny, you re again using spreadsheet logic in determine why people buy houses. Security is one of the most important. If some one finds a house that is good value, but not necessariyl cheap, and the ratio of rent to buy is adequate, they will buy. Whether it goes down a little is really not important to the majotirty as they have a 'home' as they plan to live in it from a long time. Even if it goes down a lot, they will not sell as they need some where to live and would happier to keep paying the mortgage.
Penny, i do hope you find something that is good value in a good suburb, with good schools, good transport, good sized blocks,but I dont think there will be many that will be at 40% off in such places.