Having just had our coach in for some extended warranty work I can say from experience that many of the problems are factory related - purchasing cheap parts and components and skimping on some sound engineering practices and designs (ie minimizing costs and increasing profits). Understanding that these units are manufactured homes on wheels a lot can go wrong.
It is my opinion and experience that the dealers just want to sell units and don't want to deal with warranty work. My selling dealer had used the coach for shows and it had some premature issues that they didn't take care of during their prep but waited until our walk through. Way too many issues. When asked, the salesperson responded it was SOP and she always brought a pad to the walkthroughs to document what had to be done.
Most dealers won't do repairs or warranty work without a release from the factory and don't have any pull or influence with the suppliers which effect over 50% of the coach after the chassis. I had a dealer that actually made things worse after they were done, or thought they were done, and to make matters worse left the coach in a deplorable condition. I eventually took it direct to the factory where service is an independent group and have to charge the factory for the warranty work they do. They try to inform the factory of the issues they come across but the culture of the factory is tough to change. They do however have more pull and power over the suppliers and tended to get things resolved much more quickly.
I don't see this problem going away in the immediate future.