Selection bias. Cars that were not treated for salt, and didn't die, didn't end up in the junkyard for stories to be told.

My first car spent its first 15 years in the Midwest. No garage. Very irregular car washes (perhaps once a year when I owned it). It lasted about 20 years total. When I lived there, I didn't know anyone who had to give up a car due to rust. There definitely was rust, but not something that caused the car to break down.