[throwaway0a5e]

We've mostly negated rust proofing improvements by using road salt that's more effective at getting everywhere and using salt in more places (you'll notice that the white crusted post-snowstorm hellscape was not a thing in the 90s or '00s). OEMs have gotten good at using plastic cosmetic trim to cover the initial rust points (wheel arches, rocker panels, etc, etc,) so that instead of needing attention after 10yr the problem can be ignored until a much later date when the rust finally makes it out from behind that plastic (and your car starts failing safety inspection if you live in an applicable state).

[sokoloff]

Agreed overall, though I think that last sentence is probably a very good thing.

If OEMs improve their product so that it does not require an expensive cosmetic rust repair at 10 years, but instead the cosmetic problem is hidden so the car lasts an extra 5-7 years before becoming a throwaway product, the consumer has a net win overall.