You are so right, they will say anything to sell a camperSee stuff like this at least once a day in the RV groups on facespy. Camper dealers tell the soon to be new owners that their vehicles are big enough.
The important aspect of this is 'doing 70' with a conventional vehicle... not a 'tractor' designed for hauling.I was on a major interstate doing 70. The kind of RV that you drive blew past me. It was towing a trailer with a jeep on it.
The driver lost control and ended up crossways across both lanes and both shoulders with just the RV part. At one point the jeep and trailer were waving in the air like a hand. After it was over, the jeep tires were flat. The trailer was still attached but 90 degrees from the tongue hitch. I was second in line from the wreck and praying the 50 big trucks behind me could stop. It took an hour to clear the lanes.
THIS! Told my husband this a thousands times…. The reason I won’t get another rv he will not slow down when towing we never got into a wreck but Always thought he drove way too fast with the camper trailerI find that even when the tow vehicle is adequate, many RVers think that 75 mph is a comfortable speed for towing a travel trailer or fifth wheel.