That's because Soda was originally said by the most population dense areas of the country.

By default, that gives it a huge advantage in terms of shifting the cultural language. Especially since Hollywood often controls the cultural shifts and narratives of colloquial language.

So this isn't too surprising. It's kind of like the whole "Land doesn't get a vote" thing when you look at the Red vs Blue district voting graphs, without taking into account the majority of people live in the blue areas, and very few people, comparatively, live in the red areas.

This visualization is pretty much the same thing.