I think it's most likely caused by the one way ratchet in increased CASA imposed costs . Any other views?
You don't think it's got something to do with the (mis-)management of Bankstown airport?
You don't think it's got something to do with the increase in real estate vlaues in Sydney, with corresponding increases in rent/mortgages, as well as the other increases in cost of living?
Here's another thought:
120 years ago there would have been multiple blacksmiths and wheelwrights in every regional village or town and on most large properties to service the ubiquitous horse and cart industry.
Even in the 1900s it would have seemed impossible to think that motor cars would render the horse and cart a curiosity, a plaything for eccentric hobbyists.
In the 1970s and 1980s it would have been impossible to forsee a day where General Aviation would end. Every man would have an aeroplane or a helicopter parked in his shed by the 21st century - look at the rate of technological progress we were making!
How many electronic kits does your shop sell these days Dick? I know you don't own it any more but I bet you it's a fraction of what my mates and I used to buy in the 1980s.
I hope I'm wrong.