Interesting point. Rabies is a virus, and needs a living host. Given the long incubation period I would be very surprised if the virus had not come into Aus with the early european settlers, but died out when not transmitted. The early settlers mostly came from environments where rabies was present and much feared. So much so that even a suspicion of infection was sufficient for an animal to be shot - as per comments above. You might like to read up on the history of Louis Pasteur, yes the pasteurisation bloke. He invented the first rabies vaccine for humans and this is what he was known for at the time. Its quite a story.

Lyssavirus has an endemic host species here - bats - so there's an ongoing source of infection present even though the transmission route is complex. Basically, the bat has to piss on grass, then a horse has to eat that grass to catch the virus. Then horse dies and so does any human that's been in contact with the horse. Vic Rail was the guy who died first from lyssavirus - he was a racehorse trainer and one of the better ones. I knew him way back when, and he is still sorely missed. No vaccine for lyssavirus available or likely as it's easier and cheaper to just euthanase any affected horses before any people die.