I used to live in Switzerland plus I spent a lot of time in Germany. In both countries, I would see these sorts of huge vehicles and even smaller (yet still large) Unimog "expedition" vehicles. After speaking with so many of their owners, I came to the conclusion that most of these were used only once, maybe twice and then parked. Europe is a very long way from anyplace that you can find anything less than pavement to drive on. Many of these vehicles are built well in advance and continually upgraded by the owners as they wait for their dream trip to finally materialize. Really, for many, the build of these vehicles is all the adventure these vehicles and the owners get to feel. I remember trying to find anyplace in my European travels to feel the bumps of a dirt road under my wheels. In Switzerland, I used to drive several kilometers out of my way to a short gravel street of maybe 500 feet, just to feel like I was home in the deserts again.
I had to take occasional trips back home to California to get my fix of the outdoors including 4 Corners and Baja. Finally after 2 years of living and prepping a truck in Switzerland, I was able to have a true adventure. In Europe? Nope, I had to ferry my Mitsubishi L300 Van (Montero 4x4 with a van body) to North Africa for a 6,0000 mile journey through various Sahara countries.
In Africa, I would come across these "expedition" monsters. Usually the situation was they were either broken down and because of their complexity unrepairable, hopelessly mired in sand with no way of extradition, or, simply too wide and large to fit the tracks of the road or even squeeze through the village streets. What's more, and it isn't their fault, the Germans driving these monsters had zero bush/desert experience, they were lost and frightened in a world you and I call home. Hence, the fact they needed to take a whole house with them. These vehicles were an insult of materialism foisted upon peoples of Africa who barely had food to eat.
I made friends with one Swiss fellow in Djanet, Algeria who was camping in his broken down Unimog. He was waiting for a flatbed truck to arrive from Tunis, Tunisia. Tunis was over 1,000 miles away on the north side of the Sahara. Well, by the time this Unimog (only 1 year old mind you) made it back to its proper service facility in Switzerland, it cost my friend $30,000 in towing! No to mention his 6 month vacation was ruined in the first two weeks and his $300,000 Unimog camper was well, impractical (ie;useless).
This nice fellow and I stayed friends as he coincidentally lived near my home in Switzerland. When I moved back to California he came and visited for a 6 month camping trip. I found him a Chevy Luv 4wd with a shell, $1300. Frederik would say to me <I>"That's the best truck I have ever had!"</i>
I am so not impressed, when I see these monster "expedition" vehicles, I just roll my eyes with disgust at the waste of earth's resources, at the waste of fuel and at the absurdity of people with too much money and obviously/actually little to no experience of what a frickin' "expedition" is. Go ahead, take a trip, get yourself a Landrover, or a truck camper and take that $500,000+ and use it to help the people in the countries you are visiting.