Older cars are actually more prone to theft than newer ones, as parts demands increases. The car factories are now installing as standard equipment alarm systems and heavy duty locks to counter the high auto theft rate. Driving in the outback has its own risks. You can get to most places without a 4x4, as long as you don't mind a dirt road and don't go in the north during the rainy season. Fuel is often unavailable late at night.
Australian drivers are reasonably skilled, though timid.
They coexist well with the bicycle commuters. Australia is not in love with the automobile the way Americans are. It is less of a fashion accessory or personality statement and more of an appliance. With the high cost and poor selection of exciting cars, it's understandable. Driving, like many other aspects of Australia, is different than in the U.S., but not so different as to cause a big problem.