Having looked into RV trailers in both the US and EU, I can say that the US trailers are by and large MUCH bigger than in the EU. A quick Google search showed a trailer[0] on sale in the UK, weighing in at 3289 lb. This is a typical size that I would see being towed around where I live in southern Germany. In the US, a typical trailer[1] size could come in at ~4500 lbs. Mind you, this weight is what we call dry, not counting the weight of a filled fresh water tank, important living items (i.e. food, dishes, clothing, etc), and any other items you might want to take camping.

Although this is (slightly) on the more extreme side, "fifth-wheels"[2] are also common to see on the road. These certainly require larger vehicles to pull.

[0]https://autoline24.uk/-/auction/caravan-trailers/Bailey/Pega... [1]https://rv.campingworld.com/rvdetails/used-travel-trailer-rv... [2]https://rv.campingworld.com/rvdetails/used-fifth-wheel-rvs/2...