For a demonstration of the important relationship between brand and product quality, look no further than Tide detergent, as profiled in this New York Magazine piece by Ben Paynter:
Shoppers have surprisingly strong feelings about laundry detergent. In a 2009 survey, Tide ranked in the top three brand names that consumers at all income levels were least likely to give up regardless of the recession, alongside Kraft and Coca-Cola. That loyalty has enabled its manufacturer, Procter & Gamble, to position the product in a way that defies economic trends. At upwards of $20 per 150-ounce bottle, Tide costs about 50 percent more than the average liquid detergent yet outsells Gain, the closest competitor by market share (and another P&G product), by more than two to one. According to research firm SymphonyIRI Group, Tide is now a $1.7 billion business representing more than 30 percent of the liquid-detergent market.
The technology behind Tide–the alkylbenzene sulfonate surfactant–was so revolutionary when it was introduced that it actually led to an increase in the amount of clothing people now own. And Tide's brand, scent, and effectiveness is so deeply associated with cleanliness that Procter & Gamble has been able to command a 50% price premium over its competitors since the late forties.
It's amazing what brand trust and loyalty, when mixed with truly good technology, can achieve.