I have also been in Sydney for about 15 years and agree wholeheartedly with Off Tap It is a slow process. About 2 years ago the North Narrabeen Sports High School took down the Rugby goal posts and installed AFL posts, I nearly ran off the road when I saw first saw them.
Another interesting take on this is that there is now enormous pressure up here on the Big private schools to introduce AFL into their curriculum. This is as a result of the pressure from Parents and the kids themselves. Whilst this may have a huge effect on Rugby, it will have a knock effect for league eventually. As has been said, slow steps.
If Kings school in Sydney ends their Rugby programme it is going to be difficult for me to suppress the desire to run the kids over when they are crossing the road.