So my question is this...I am no auto engineer or expert on metallurgy, so what is the root cause of this. Is it the grade/quality of the steel? The design of the frame rail (boxed vs. open)? Inexperience in making body on frame vehicles?
I have tinkered on cars my whole life and I don't think I can ever recall a frame rail rusting to pieces. Granted, I've seen some pretty f'd up by accidents, but I always was under the impression that the frame rail is supposed to be the back bone/strongest part of the vehicle.
Oh, and having said that ... other then designing the shape of the rail, the ability to construct one to a certain strength does not seem that difficult that someone like Toyota could not accomplish it.