Apart from what has already bin said here re cost of doing business in OZ etc one of our biggest problems in Oz is that the Airlines are their worst own enemies.They have undercut each other so much that it's getting very difficult to make a buck for the outcome laid & IMHO it's not sustainable.
Big land theory also with not many people about,Oz simply doesn't have the masses & therefore like our pathetic road infrastructure aviation & it's associated costs are spread over but a few.
Wmk2