"I wouldn't describe South Morang as anywhere near desirable!"
That is the problem there is housing that is affordable to many of those that say it is unaffordable even in the cities. It is just that so many don't want to live there because it is not "desirable" in their eyes. If more of these people did move there then in the space of 10 years the suburb will likely transform into a more desirable location. Suburbs that were not so desirable many years ago are now sought after areas.
Keep up the area prejudices it leaves more for those that can look beyond what the area is like today and look further into the future.