They are, same with cosmetics. Some of the old school "semi-high end" brands such a Lancome and It Cosmetics,also high end brand YSL and Giorgio Armani Beauty are actually owned by drugstore brand L'Oreal which also owns Maybelline and Garnier.
Coty the makers of that horrible smelling drugstore lose face powder also owns Marc Jacobs and Gucci brand cosmetics. They also own drugstore brands CG and Rimmel London.
Also are private label "brands" which manufacture many products for many companies and even ingredient rights owned, which are sold to indie companies, such as Tati's Halo Beauty brand.
On a different twist, there are food products that are the same thing but has additional ingredients, like a Hershey bar, a Mr Goodbar is a Hershey bar with peanuts, krackel is a hershey bar with rice, etc. think Milky Way and Snickers are the same thing with exception Snickers has nuts..
Cereal is similar, Kelloggs Froot Loops and Apple Jacks are the same thing different flavor, General Mill's Kix, Trix and Cocoa Puffs are the same shape as well different flavor. Not including Corn Flakes and Frosted Flakes, Rice and Cocoa Krispies, etc which are billed as same product different flavor, Mounds and Almond Joy are the same thing one has nuts.