Ok, lets run with this one a bit.
It's not obvious from the photos you posted exactly where you're storing your sleeping bag, pad/mattress and tent. I'm assuming you'd do the logical thing and put them on the roof since they are bulky, and light. I'm not sure if you've actually looked at this, but 4 sleeping bags, pads, and a family tent also take up a crapload of room on the roof (or anywhere you care to put them). My warm sleeping bags take up about a 2'x2' footprint each. The Tent is about 12x36, and the sleeping roll... 12x24 at best. So that's 9 sq.ft. for 1 person, 15 for 2, and 27 sq. ft. of rack footprint space for 4 people. A small rooftop tent (4x4 folded) takes up 16 sq. ft of space, and a large (70"x48" folded) takes up about 24 sq. ft. When you consider most people fold up their sleeping bags in the tent, and there's no need to bring mattresses... the RTT doesn't really take up much room at all. It's a pretty easy to justify luxury.
Even in a best case scenario using my compact bags as an example they pack down to about 12x18. So at best you could get down to 17 sq. ft for 4 people.
The 4 foot length of an RTT leaves a lot of room at the front for your fuel and other parts, the only thing really that might get bumped is the spare tire. That could be easily accomodated on the back bumper if you wanted. And the GRP boards go on the sides anyway.
The only real disadvantage to the RTT is the weight of the thing. But at 110 pounds, it's not actually that much more than that spare tire is (assuming mounted).
As for the trucks in the picture... you're right, the first truck would be giving up a lot, since he's obviously got everything he needs right in the truck. But... there's only one person in that truck. If there were 2, or heaven forbid, 4 people in that truck... he's not going to have an empty roof anyway, now is he?
The second truck, it's hard to tell, but the back half of that rack looks empty. But let's assume it's full of Pelican cases. If he puts an RTT up top, that will remove his tent, pads, and sleeping bags from inside the truck. Now some of the displaced Pelican cases can go in the truck.
Then you go on to try and justify the fridge (or cooler!), and anybody who has done any non-vehicle-dependent travel is going to chime in and say that just for the 40lb weight of the fridge alone you could have 80 dried meals. There is no real justification carrying a fridge. It's absolutely a luxury, one which you have managed to justify for yourself.
People go canoeing or backpacking for a week at a time, easy, with only the stuff they can carry on their backs. Everything else is a luxury. Trying to say that one person's luxury is justifiable and another person's is not is pure hubris.
Edit: The only serious drawback to the RTT I can see is that if you have to bail on the truck, you can't take your tent and bags with you. But then, when I see neatly stacked Pelican cases with gear in it, and a fridge... Well, you only have 2 hands. Let me know how it works out for you.