I would disagree with your premise, there is nothing significantly better with the Volvo than the Camry to justify a $40k difference. Quality, reliability, ride quality, resale value, etc. make the Camry and many other low end cars very good choices. Now the Yugo would be a different story. It is the prestige that makes the Volvo worth $40k more.
But I agree with your conclusion about RVs, quality is bad regardless of price. And the more things, features, bling you add to an RV, the more problems you are likely to have.
There are maybe a few exceptions, Airstream (you pay a lot for quality with few extras), other brands as well, both expensive and inexpensive. My $30k unit seems to be an exception, better quality than my last 3 units spanning 18 yrs.