I don't think world economic growth affects people's purchase of soft drinks. The key issue is that Pepsi's not simply soft drinks. The soft drink business itself is mature and growing very slowly. Last year growth for Pepsi-Cola and Coke took a hit when both companies raised prices. Even if momentum picks up, sales of carbonated soft drinks will remain relatively weak.
Overseas markets offer the potential for more growth.
Already, over a third of revenues come from outside North America, and those markets are growing much faster than at home. PepsiCo claims its international soft drink sales grew faster than Coke's in nine of the last 10 quarters, helping it gain market share in most of the biggest 25 foreign markets. Plus, with more powerful brands from Quaker in its arsenal, Pepsi will have greater leverage with supermarkets and other retail customers. As it is, chains tend to look favorably on the company's snack foods. They're easy to stock, since in most cases PepsiCo employees come into stores and shelve the goods themselves.