Starbucks is a coffee shop that makes money by selling coffee and other associated snacks, beverages and accessories. Number of coffees sold is a function of foot traffic into the store. The more peopel visit starbucks, the higher their revenues. The reason why Starbucks would have multiple stores is to increase foot traffic:

1. Convienience – Crossign the street is an entry barrier at very busy junctions. Especially in a car, people will drive past looking for the next coffee shop vs make a  u-turn. Having coffee shops on both sides help in capturing traffic going both ways.

2. Avoid competition – Starbucks can avoid foot traffic loss to competitors by preventing competition from taking uo the same space

3. ‘Become known’ – The location can be known as a coffee destination so it is top of mind when people need coffee. Overall foot traffic to location increases.

4. Reduce supplier cost – this may be a minor point, but there can be increased efficiencies of restocking when 2 stores are nearby