OK, here is the BIG difference.
Coke decided to get RID of "Coke" and replace it with "New Coke" that tasted different, supposedly due to taste tests, and was closer to the flavor of Pepsi.
People said, If I want and Like/Love the original Coke, that is what I expect it to taste like, NOT this newer sweeter stuff. If it is in the Red Can/Bottle, I WANT COKE, not the new stuff.
On the other hand, many brands add new options, and Coke has done so over its lifespan.
But don't change your original product.
A similar marketing issue was with "Kentucky Fried Chicken" when it switched to "KFC" and tried to add Rotisserie Chicken.
So much so, they brought back the Colonel and re-emphasized its main product, FRIED Chicken.