RVs are designed and built with what amounts to shade tree engineering. Nobody does an engineering analysis on each element - they just go with experience from previous models (which may or may not have been all that great) and extrapolate to the new situation. If enough complaints come in, they may learn something for the next go-around, but chances are any individual problem will only effect some owners, some of the time, and word won't get back to the factory guys.
RV layouts change all the time, trying to find floor plans, features and price points that attract more buyers. A modified design moves something or increases size (e.g. bigger tv, more kilowatts) or adds something (e.g. an electric fireplace) and the so-called engineering group races to make changes to include them while not requiring new wiring harnesses, build procedures, or expensive components. Somebody eyeballs the changes and says "looks OK" and that's pretty much the extent of it.
Several years ago I had the opportunity to chat at length with Fleetwood's Production Manager, responsible for all their motorhome product assembly lines. His biggest headache at the time was rapidly changing expectations for TVs in the motorhomes. Flat panel tvs were quickly increasing in size and quality and having the latest & best tv was a major selling point in mid-high end coaches. Every time the marketing types came in with an improved tv offering, engineering did a quick revamp and they shoved it onto the assembly line. And the problems snowballed. Overheated electronics, overloaded circuits, inadequate mounts for the larger/heavier tvs, etc. He started to veto production changes because they couldn't provide assurance the changes would be of decent quality, but they had no process in place to do that and no time to do it if they did. So it was "test it in the field" all the way. The engineering guys gradually learned what had to be done to handle the new and larger tvs and the problems dies down, but meanwhile hundreds of coaches had been built and sold and the inadequate designs delivered to buyers. The problems went on for a couple years but once they were post-warranty the factory loses sight on them except through owner clubs and factory-sponsored rallys.
