I think a big part of the problem is, and I would put myself in this category a year ago, is that the vast majority of people have their truck first and then put a camper on it. What is ideal is for people to decide what camper they want and then build the truck around it but that is not realistic unless one is starting from scratch with a truck or a camper. Or, make sure the camper you buy fits the truck you already have, something else that does not happen most of the time.
So, most people do what I did, start researching different manufacturers. I can tell you that every one of them I researched, and there were several, state directly on their website that the campers I was looking at were designed for a 3/4 ton truck. Websites complete with photos of the campers on 3/4 ton trucks and marketing brochures stating the same. Then I go to the dealer websites and see the same thing, and hear the same thing when talking with them. I even talked to a manufacturers rep that told me a particular camper I was considering would work fine on my truck. In fact, it would not just going by the payload numbers, axle ratings etc.
Was I ignorant? That may be a little strong but I definitely was not as educated as I should have been then, but certainly am now. So, I trusted the manufacturer, dealer and Ford sales person (prior to buying my truck) to help guide me to the right decision.
After buying the camper, and after getting a big dose of education, I made a decision to upgrade my truck to be able to carry my camper safely and within the published specs.
Most people who buy a truck camper for the first time go through the same process and learning curve I did.
I just want to help people avoid the mistake I made by sharing my story so that more people become better educated in this area and ultimately be safer on the road.