Re: what kind of metal? 5-year lifespan
They built their vehicles to last 5 years, then to be traded in and recycled.
Japan literally had tax and registration laws that favored such activity, so as to keep their home auto industry and economy cooking.
It was only after exporting to the US and ultimately to meet the US consumer demands - for cars that didn't start rusting weeks after buying - did the Hondas, Yodas, Datsuns get serious about making good cars even better.