I think you are missing the bigger picture.
Regardless of how well or how poorly an item sells, regardless of a company's reputation, and regardless of what you and I "think" about their product, if significant quantities of their product is being RMAed that is going to kill the profits of that product. If its a very high failure rate it might bankrupt the company. OCZ has some products that have been claimed to have a 40% return rate during the warranty period. Oh look, OCZ is filing for bankruptcy. Coincidence? I think not.
Even if the claimed return rate is 1/2 of reality, that's still 20%. If just 1 out of every 5 customers is having to do an RMA you can expect people WILL be upset and people WILL complain. Just think about how many do a second RMA and that one fails too!
The bottom line, products should not regularly require an RMA during the warranty period. Both so a customer gets a feeling that the product lived for the duration of its expected life and because the company doesn't need to go bankrupt while dealing with failed product processing, return shipping, customer service calls/emails, etc.