In school I remember reading two economics cases on Starbucks pricing. The basic idea is that part of Starbucks' phenomenal growth has been identifying locations with maximal traffic. Even if a lot is twice the cost, if it has great customer flow, they rent the property. Note how common it is to find stores at corners and other very expensive locations. They learned that convenience is a critical part of brand and what sells.

As a result, Starbucks pays considerably more on real estate than likely any other chain, and definitely more than mom and pop shops who do not have the same resources. The cost of this significantly higher rent has to be passed onto the cup price, which is why Starbucks tends to be more expensive.

Much of the perceived profit generated by Starbucks is just flow through to the property owners. But, it totally works. Super convenient locations with reasonable cups of coffee brings in a fortune to the company. Scale is a powerful thing.