Brand names for household products came into their own not to differentiate identical products, but rather to differentiate identical-seeming products. I.e.. because of the scandals of adulteration in the Victorian age.

http://www.artisanfoodlaw.co.uk/history-of-food-law/19th-cen...

https://books.google.co.uk/books?id=U29jOkKqI2kC&pg=PA96&lpg...