Better engineering and a desire for ever-higher fuel economy means that today's cars are made stronger than ever before (when new) but with less metal. Less metal means the frame is compromised more quickly by corrosion.
All but one of my previous vehicles had engines and interiors that were perfectly fine at 200k miles but the frames and bodywork were so rusted out that the whole car was essentially a loss.
Car manufacturers COULD design a far more rust-resistant car, and it wouldn't even be that hard or much more expensive. But of course when your business is pumping out millions of a thing, you don't have much incentive to engineer it to last longer.
I started spraying wool wax on the undercarriage of my car. 3 years in midwestern winters with salt and 0 rust on the underbody. Not a complete solution but helps, as I tend to keep cars for 10+ years.
Is it really a desire for "ever-higher fuel economy?"
I would have no problem driving a 10mpg car that had character, didn't look like every other car on the road, or had some sort of unique value to it. But regulations are arbitrarily increasing fuel economy requirements which drives every car to use smaller engines, less powerful engines, and end up looking like a half-used cough drop.
I think if manufacturers didn't have to waste time with that they would be willing to invest more in things people actually care about, rust resistance being one of them.
Better engineering and a desire for ever-higher fuel economy means that today's cars are made stronger than ever before (when new) but with less metal. Less metal means the frame is compromised more quickly by corrosion.
All but one of my previous vehicles had engines and interiors that were perfectly fine at 200k miles but the frames and bodywork were so rusted out that the whole car was essentially a loss.
Car manufacturers COULD design a far more rust-resistant car, and it wouldn't even be that hard or much more expensive. But of course when your business is pumping out millions of a thing, you don't have much incentive to engineer it to last longer.