First of all I had a Titan which was roughly 300 lbs lighter than a comparable Off Road 4X4 Armada. I was getting 13.2 mpg driving to work which entails expressway, backroads, highways with a lot of stopping, passing, and slowing down. The best was going from Chicago to Arkansas and was 16.5 mpg with cruise control on and doing 65 mph for one tank. Other tanks seen higher mph and went down to about 16 mpg. This was with cruise on, none stop.
My Titan was a loaded out 4X4 Titan XE Crew Cab with the Off Road package that added lower gearing for better torque when towing or off roading. So I most likely gave up 1 mpg for that. My Pathy does 17.5 mpg where the Titan did 13.2, and I have the same gearing.
There is no way I would ever consider 2WD in a SUV. As other's pointed out, might as well get a van. In fact, if there were any full size vans that were lifted with 4X4 as in the old days, I would had opted for one of those. I like having a bed and table for camping. I know they're still made by outfitters but you pay out the @ss.
Anyhow, you do take a hit on resale when getting a 2WD. Trucks take a hit but not as bad since they have a sole purpose of hauling and many have to have one for work. SUVs are known to be Sport Utility Vehicles, not VANS. Not much Sport or Utility if you can't go places without worry. If you just need a people hauler and towing capabilities, there are some darn nice conversion vans out there. Like I said, I thought about a conversion van but they're 2WD. If I have any vehicle with standard rear wheel drive, it MUST have a 4WD part time option. If for nothing else, safety when driving in pouring rain thunderstorms and the snow. If you have a boat, good luck getting off that slick ramp with 2WD. If you hunt, good luck getting to your hunting spot. If you camp and not "RV", good luck in getting to those good spots while not getting stuck. If you want "Sport" and "Utility", you won't get it with 2WD. If you just want "Vehicle", then go and get 2WD.
Did I make my point?
Have a good one.