Weight savings, CAFE requirements, gas mileage, etc, They have to trim weight with each new design. Smaller gas tanks, Auto start/stop, Aluminium panels, front air dams only inches off the ground, awful driveability. I'm not sure why everyone doesn't understand this..
I for one could care less about a few MPG... I would rather have great driveability and real steel, but there are many truck buyers that choose solely on this, they could care less if it's Ford, GM, Dodge.
Either way, no need to complain. Either keep your 1999 truck, or adapt.