Obvious build quality issues is one thing, and disappointing for sure, for the many that spend a lot of money in RVs.
But care, storage and upkeep are likely as big an issue as quality. But not too many would admit to neglecting their RV even though, based on the large numbers of them we all see everywhere that sit out in the sun, rain and snow all year round, many do neglect them.
No different than any other "toy" or vehicle. Sure your _______(fill in the blank) can handle a trip to the desert or getting soaking wet or packed full of snow, mud or slush, but subject to those conditions constantly, they deteriorate much quicker than things that are well cared for.
Sometimes it's intentional, and expected. Part of the job so to speak, but more often it's folks that just don't care for their stuff and then wonder why it doesn't last, often comparing it to a similar machine they see that is in much better shape.
Those that tout the good quality of something are more likely the folks that take care of their stuff and those that tout the poor quality are more likely the opposite.
Does t mean there aren't defects and some poor quality stuff out there but even the poor quality stiff would last much longer with more effort in caring for it.