Why are Truck Campers so poorly made?

Having already owned a 2001 Fleetwood Terry travel trailer which literally (fiber board) split in the front (within 5 years of purchase) and subsequently caused all kinds of roofing issues...wall leaks...and then mold, I was really hesitant in buying ANY RV. $16,000 down the drain and I will be lucky if someone comes and tows it away for free. Now mind you before you respond with judgments, this TT was kept in the mines over the winter months and was only pulled locally within 100 miles of our home. What a POS. I agree that most manufacturers create a half assed product... WHY you ask? So they don't last long, and us consumers have to purchase more than 1 or 2 recreational vehicle in a lifetime. That said, I finally decided to buy a Truck Camper last week. I am not ready to just throw in the towel on camping mind you. I love it too much. So in my research, I decided not to buy any of the newer models with the fiber board walls and rubber roof. (YUK) and I certainly can't afford to buy a Big foot or an equivalent all fiberglass shelled camper. So I decided I would be better off buying an old (Fiberglass roofed) 1973-76 Amerigo. Now mind you this camper is a total gut job. 40 years of non maintenance and rot. But hey, I gotta better shot at rebuilding this thing and getting another 40 years out of her than I do with what is on the market our there today.