Given that the GA fleet is ageing, and the average age of aircraft seems to
be 40 years, what happened 40 years ago that a whole fleet of aircraft were brought into Aus?
Piper and Cessna did what most car manufacturers did in the late 60s and 70s and that's overproduce and sell cheap. They were doing well until the late 70s and particularly the 80s where civil actions against them started to mount up due to faults and poor legal advice. This had two effects, one, to increase price of the aircraft to afford liabilities and two, improve the technology of the aircraft to avoid liabilities, which in turn pushed up the price. Because the market was flooded with so many low cost aircraft only a few years old the market dried up and both companies hit the wall and production of GA aircraft virtually stopped. Today the average price of new GA aircraft is way beyond the average person so sales are relatively sparse. Add to this modern infrastructure and cars can get you quickly to most locations traditionally served by light aircraft in the past.