Exactly - why not put rust protection from factory into this package!
Even if it costs 300$ more - people in the rust belt would buy it without thinking twice.
I have long joked about it being a conspiracy, the car producing states in particular, Michigan, Ohio in the Midwest dump massive amounts of salt on the roads, AND they also ban studded snow tires. That they have an industrial base in making cars.. Coincidence, I'm sure it is!
I'm in Washington State now, we can use studded tires in the winter, and they seldom use road salt here, my 2009 truck frame looks almost like new, no significant rust. My 2004 Land Rover is likewise in great shape, I did POR-15 the entire frame last year when I did extensive work to it, so it even looks better than new.
I'd rather have seasonal tires and drive on unsalted roads, ice and snow, than have a car rot away from corrosion.
As to engineered prevention, the newer cars are far better than they used to be about rust... here on the OP we are discussing a truck that is 17 years old.. Go back about 20 years, and you'd be dealing with rust on vehicles that were 5-6 years old, or less.
As an example, in 1990 I bought my second el cheapo used car, with 60K miles (then considered significant, now days, low miles). That 1984 car had been a NY State car, and there was not much left of the supporting frame of the hood, and it basically had carpet floor pans (no metal left). Also, one day the brake line to rear brakes blew out, from RUST.
Bottoms of the doors had been repaired with fiber glass and bondo... not much left of the original metal left there.
I spent considerable time under that thing with a wire brush, Rustoleum rusty metal primer and Rustoluem paint. I welded in new floor pans, etc. I was able to make it last through College, with my rust fighting efforts... but there is no way it would have made it without extensive help.
In comparison today, even in the salty states, most 6 year old cars in in pretty good shape without extensive rust.
That said, continued improvement is always welcome, but even a Stainless Steel frame will rust with continuous exposure to road salt. Coatings have improved, and one of the best ways is to start with a hot dipped galvanized frame. They make new Land Rover frames that are hot dipped galvanized, they seem to hold up very well. Now why the OEMs don’t make that an option.. who knows, seems it would be a tiny cost add over the price of current new vehicles, but a cost many people would gladly pay, even if it were an option at extra cost.