I don't believe property will double every 7-10 years into the future - even if it did in the past. It can't when you are coming from such a high base. You are talking an exponential curve. If wages, inflation, and other numbers is not also exponential you soon get to an illogical place.
For example if I assume 4% CAGR in rent and wages but 10% CAGR in house prices (gives you the doubling in 10 years roughly) you end up with combinations like:
* Rent of $500 / wk, wages of $1700 / wk, house price of $1.5M (1.7% yield).
* Or if I take it out further you might get a combination of rent of $936 / wk, wages of $3120 / wk, and house price of $6.3M (0.08% yield).
In short, they can't stay disconnected forever and if you beleive the property doubling every 7 to 10 years story then you have to believe similar things will eventually happen to rent. Hence the thread title being rather insightful.
Wages, surely, increases at a % so it is exponential as well. However, historically the price of a given house increases faster than wages (the anecdotal evidence is that 'affordable' housing for people on ordinary incomes is moving further and further out).
Obviously, as YM's calc shows, it means that a given house becomes less and less affordable for the average income earner. Yet that's exactly what we've seen. How does this work? One answer: average wage earners rent average houses. The average wage earner today DOES not, because he CANNOT, rent the same house his counterpart did 30 years ago. Why? That house is no longer average.
For any given house, it starts as an outer suburb house (rented by average workers), then in 20 years becomes a middle-ring suburb house (rented by, say, young professionals and white collar workers) and in another 20 years becomes an inner city suburb (can only be afforded by highly paid people, or, even more likely, those average workers who bought the place 40 years ago and those now-middle-aged white collar workers who bought 20 years ago).
Somewhere along the line the old house is demolished and units / townhouses built in its place. That's why we talk about gentrification, and why areas get redeveloped.
YM's calc assumes the same type of people will keep renting the same house. In practice, that doesn't happen. The 'worker suburbs' of 30 years are NO LONGER the workers suburb of today. What used to be way out in the sticks 30 years ago would be a middle-ring suburb now. Why? Because the population is growing, and the number of low, average and high income people is also growing. If you have 500 highly paid people, they need, say, 200 houses. If the population doubles, and you now have 1000 highly paid people, they will need 400 houses. So they're going to buy into areas that were previously inhabited by people on different incomes.
Now, will property double in the next 7-10 years, if you use 2007 as a base line? Maybe not, because we've had such strong growth in the last 7-10 years. I personally am expecting a stagnant or falling market for the next couple of years. But if you use, say, 20 years, then it's more than likely that you will have 7-10% average growth.
Still not convinced, YM? That's ok. I gain nothing whether you buy or not. Whether you lose out by not buying....... that's your problem only.
Alex