But your graph was not median price per square metre - it was simply median price based on a "trend". I'm saying your trend is impossible as it can't be financed.
If you mean price per square metre then you are talking about something more logical.
My graph showed the median price for Sydney, Melbourne and Brisbane... our biggest cities. As discussed in previous post (and as per other large world cities, London, Paris, New York etc.) eventually only the investors and super rich can afford to buy in the big cities. This allows city prices to increase exponentially. The ripple-down effect leads to rises in the outer suburbs. People will always find the cash to live somewhere, either by buying or renting. After all, what other option do they have? And where-ever they choose to live, their demand will push up the prices in that area.
No, I don't believe it can increase exponentially
forever... but until such times as Australia actively encourages and implements extremely high-density development similar to other large cities, the price trend
will increase exponentially. The move towards high-density development will occur, but slowly, because people living in the more affluent areas do not want their suburbs subjected to row upon row of skyscrapers.
Any local government that tries to tell the folks in Sydney's Northern Beaches or Melbourne's Toorak that their nice leafy suburbs will be flattened for high-rise will not be elected for long. So the trend towards higher density is so slow that eventually only the investors and the rich can afford to buy in the city. Everyone else rents, or moves further out.
It can also be argued that there is a hard limit on how far high density can go. What happens when all the worlds cities are completely full of the highest skyscrapers that man can design. And the population keeps increasing... then what happens... prices start to move exponentially again, and we start to build highrise across the entire planet. What happens then? Eventually Earth will look like Coruscant and then it's time to inhabit other planets, but that is a topic for another thread
http://en.wikipedia.org/wiki/Coruscant#Overview
(EDIT: I have started a new thread about Megacities here...
http://www.somersoft.com/forums/showthread.php?t=38322 )
Cheers,
Shadow.