<<But the Vanagon hasn't.� Still the same (maybe more) weight, same
suspension, same aerodynamics.� And the load rating system for tires
has not really changed.� So stronger/better handling/longer
running/better rubber compounds doesn't change those numbers are the
side for maximum load and inflation.>>

No, the mfg's tire pressure should NEVER be overlooked, or ignored.

Yes, the vehicle hasn't changed, it's still the top heavy, wallowing in
the wind old beast.

The tire's aren't stuck in a time warp as the vehicle is.

Fortunately, they have advanced with time.