The forum is an extension of a club that is interested in modiying Toyotas. Most people into the "late model" car scene tend to be into posing rather than modifying. The fact that Toyota haven't released a decent car in Australia for a long time would contribute to the amount of older cars here.
The other point is that the majority of the people that post a hell of a lot, are kids. Kids tend to find it hard to buy late model cars.