I can't speak for all truck owners, but my primary reason for having a non-4x4 truck is that I'm not in Congress--I can't spend your money to buy my truck, I can only spend mine. Well, I mean, if you want to give me the money to cover the difference, I wouldn't tell you to go jump in a lake, but somehow, I don't see that happening.
That and in Oklahoma us city folk only need 4wd for 20 minutes a couple of times per year.