Equating a brand name to a product is similar to equating a writer to his or her books. An author's work becomes inextricably linked to his or her person so much so that one expects only one genre of work from an author.
Agatha Christie, for instance, had to use a pen name to sell her romance novels. One does not view the author as a dynamic and complex individual. One brand seem to fit all.
"..The author also constitutes a principle of unity in writing where any unevenness of production is ascribed to changes caused by evolution, maturation or outside influence."