Why are Truck Campers so poorly made?

I can assure you as someone who has been a carpenter and built homes both steel and wood minus the appliances this man is not far off when he says 3 grand in materials. Im building my Own Metal home right now and its 2100 square feet and will cost less than a New name brand truck camper. And that's ridiculous. I cant speak for all campers though. Just saying I don't think they are worth it. When I buy a new one I would like to have something I could park in the trees for 10 years and expect to come back and see no leaks/ no rats/ no rot/ There is only one way to ensure this and that's a solid aluminum Box and frame and skin. I may have high expectations But I know what I want and as a builder I know it can be done. In my own opinion I prefer durability above all else, I need something rugged. I'm hoping these all aluminum TC's they are coming out with meet my expectations, Im going to look at them and if not Ill have to buy a Tig welder and get busy lol, It maybe not as pretty but it will last.