AFAIK, the reason why second hand cars are cheaper in the U.K. is that they rust out. They rust out because in the winters the poms put salt on the roads to melt the ice. Same for Canada (last I knew) and I'm guessing the parts of the U.S. where it snows.
In oz, you'll see any number of 10 year old used cars that are in excellent condition and will keep going for another 10 years with little more required than regular servicing.
DIVOSH!