I used to do a lot of back country hunting and fishing, and a 4WD was pretty much a must, now I do back country photography (amateur) and find the same need.
I have used 4WD several times (RV'ing) on gravel or wet grass over the years and my truck is my daily driver so 4WD really does help in winter where I live.
IMHO anyone who says they will never have a 4WD has never been in a position of needing it, especially out of cell phone range and miles from anywhere.
For those who never go off pavement or drive a truck in winter, by all means go 2WD, but you wont really save much, money or weight wise.
Besides the above, where I live, you have a hard time giving away a 2WD truck, so resale or trading in is a big factor.
The cost of more maintenance and fuel with a 4WD is really a non issue with the newer trucks.