Because if marketing strategies..or lack there of!! Packaging and advertising go a long way..here in America we tend to judge books by their cover "Oh would ya look how pretty the package is on that rat poison that I don't need...I WANT IT!!!"
What is 'leading brand'? It just means what the media is hyping the most or getting paid the most to promote. Most generic and store brands are made by the exact same companies that make the major brands. The only difference is in the packaging and marketing. Products with the fanciest packaging and recognizable name cost much more but really all youre paying the extra for is that packaging and advertising and the name. Go to Walmart and look at Libbys frozen corn. Right next to it is Geat Value frozen corn in its plainer package. Both are produced and packaged by the ConAgra company. They get away with this because they know theyve hoodwinked the general public into believing its better if it has a better package and big name.