There are dozens of items in the build of an RV that some buyers would gladly pay $500.00 or more to improve. Tires, sound systems, flooring, furniture, video systems, plumbing system, battery capacity, HVAC systems, cabinetry, roofing etc. are just some of the possibilities. The trouble is, what is $500.00 or more important to one buyer is absolutely unimportant to another. To improve and upgrade them all would probably double the price of the unit, and we all know that one of the most important considerations when choosing a RV for purchase is the price. Construction where none of the components are visible is an area where expensive improvements likely would not net additional sales, so it is an easy area to do the minimum necessary to make the unit functional.