You also need to remember that, to Americans, any soda with cane sugar in it is fancy. A soda that doesn't have corn syrup in it, what a special treat! I've seen special 'real sugar' variants of big name sodas in stores here, and they'll also sell Mexican versions of the standard Coke/Pepsi mainstays (and Jarritos, another Mexican brand) because the bottling plants in Mexico don't use corn syrup, so they're ~fancy~.
They kind of are, too. The difference between corn syrup soda and sugar soda is mostly a texture thing. Being syrup,, corn syrup is a bit more thick and goopy, so sodas with cane sugar taste a bit lighter and snappier.