In my early crossings of the Nullarbor (1970s) I enjoyed looking at the numerous cars abandoned behind the old homesteads, where intrepid travellers had been forced to proceed otherwise when their cars expired, and I used to wonder about some of them. There used to be a Daimler, 1950s, abandoned at Nullabor Station in among the dead Holdens and Fords. Who in their right mind would drive across 1,000 miles of very bad goat track, which it was then, in an antique (or even new) Daimler Conquest? Not a lot of Daimler dealers en route.
It's very dry out that way, so the derelict cars are probably still there, badly suburned but not too rusty. There's just no value in trying to cart them away, so there they stay. There are lots of old cars on remote outback sheep and cattle stations which weren't worth taking into town (several hundred miles away in some cases) to repair; so the owners would dump them down the back, and presumably Mum and Dad would jump in their plane, fly to the town, buy a new car, and one of them would drive it home.
It's getting worse these days as cars are ever more throw-away. I've seen late-model cars abandoned by the highway, plates removed. Not worth recovering.