Thats a nice truck. An '86 d60 f350? Not even any rust in the wheel wells. What happened to the poor guy? Looks like he's a ways off of the road. Say what you want, if 2wd is the only difference, you're gonna be stuck way sooner. That blue plow truck would've needed 3500lbs in the bed to come close to pushing the same snow. 4wd gives you a drive axle with the heavy diesel right on top, plus the weight of a plow or winch. As Mel said earlier it helps the truck handle better while under way. The touque is distributed to two drive shafts, 4 axles, this decreases the chance of breaking something and offers a built in spare driveline to get home if something does break, I have driven a front wheel drive truck after the rear driveshaft spit out. 4x4's have a higher resale value. When it comes to treading lightly, a 4wd will leave less of an impact on the trail. Stock, a 4wd sits up higher, offering better ground clearance. 99% of 4x4's have low range that takes stress off of the trans when things get real sticky. I guess someone will argue thats not needed either. When it gets muddy, sandy, or snowy, 2wd is a waste. If your travels are limited to paved or well maintained dirt roads, I understand no need for a 4wd. If you hunt, cut firewood, plow snow, go to the beach, dunes, farm, navigate a construction site or go anywhere else a built, maintained road is not present, 4x4 is too convienent not to have.
I could argue that a 300 straight six could do the job just fine and the expensive diesels aren't needed. I could set up a straight 6 truck to do so but why work around all of the short comings instead of just starting out with a better setup. I'll keep 4wd, set it up with lockers, good tires, ballast in the truck and a 2 wheel driver will be white knuckled and stuck a hundred miles behind at the end of the day.