Part of the issue must be too much washing and not enough driving, lol. My 05 Durango is a week away from 200,000 miles, driven year round, never garaged, and was last washed in 2009. Couple small bubbles on the gate, that's all. A local guy has an 06 with half the mileage, always clean (even in winter), garage kept, and the bottom 4 inches of his gate is GONE!
No manufacturer is any better, salt is salt. In 2009 the local garage was replacing the rusted out rear trailing arms on a low mileage 2005 Ford SUV, can't remember if it was an Exploder or an Expedition. Four years old and ready to lose the rear axle. Garage kept vehicle.
Drive them hard all day, don't wash them, and let them sleep outdoors. Seems to be working for me. Gives time for everything to dry out? Maybe mine just don't sit still long enough to rust? Dunno, just glad it's still goin.