You say that like that's not an interesting observation. On the contrary -- that is a common observation that people frequently make about Coke in particular. It doesn't taste good, but people buy it anyway because it's Coke.

The actual form of the saying is something like "if every Coke factory burned down, Coke would be back in business the next day. If you hit every Coke customer on the head, Coke would be out of business the next day". (The idea being that if Coke's customers all forgot they were Coke customers, Coca-Cola wouldn't be able to grow a new customer base on the strength of their product.)