The industry builds what the people buy. They for the most part want a big box with a lot of glitz and bling. The manufacturers see and endless supply on this type buyer. The buyer is often a new or unknowable buyer and is not thinking about quality or how long the RV will last. They are just interested in a low monthly payment and hook up to go camping.
After they get burned a few times, they will give up or a few will try to move up the food chain to a more expensive unit.
Another side of the issue is maintenance on the RV. You have a house that is built lightly to keep the weight down and you go dragging it down the road , bouncing and shaking it. A lot of the buyers lack the knowledge to properly maintain the equipment and many cannot afford the extra budget to get the work done.
Many of the RV dealers do not have well trained people with the work ethics to make a proper repair.
There are many problems with RVs, but you can get some decent ones, but you have to get way on up there in the cost to get the quality. And you will still have some problems...it is the nature of the beast, but you should not be having structural frame problems and leaks due to poor construction.
Build it right or do not build it.
Ken