Errr.... you have occasionally been in convenience stores and supermarkets, yes? Restaurants that serve both Coke and Pepsi are rare, yes, but stores where you can buy either are an everyday thing for most of us...
Given how precious space is in supermarkets, and how companies pay for prominent placement, the whole side of the aisle devoted to soda at mine inclines me to disagree.
What I meant was Coca Cola probably sells more soda in places like fast food restaurants, gas stations and pubs than in supermarkets. And probably at higher margins, too.