Something interesting about a camper like in the picture in Europe, to me, is where the axle is. It looks much more centered than the campers I see in the US and I have no idea why. The way the axle is in the picture certainly reduces tongue weight on the car. I wonder if the trade off is less stability at high speed? Genuinely curious!
The typical tongue loading for a traditional trailer like that is 10%. If you start getting too light it will start swerving from side to side at higher speeds and can lead to a jack knife accident from the tail wagging the dog. Most likely the trailer has heavy stuff designed into the front.
Tongue weight in Europe (EU) is much less than in the US. In Europe it's typically 4 % of the trailer weight.
Instability at higher speeds is less of an issue in Europe, as the maximum allowed towing speed is 100 km/h. Depending on the type of trailer and country, it can also be lower. Trailers above 750 kg are always braked with overrun brakes and require an additional driver's license (class BE instead of B).
Trucks are limited to 90 km/h, buses to 100 km/h. As you can see, caravans and motorhomes in Europe fit right into the flow of other slower traffic.
Having vehicles traveling at different speeds, requires good lane discipline though. It is the law in most of Europe to drive in the rightmost lane possible, unless you are overtaking.