Sounds like a variation of the Starbucks problem. Starbucks is very cheap, the expensive sugary drinks would be even more expensive at any other coffee shop and

Sounds like a variation of the Starbucks problem. Starbucks is very cheap, the expensive sugary drinks would be even more expensive at any other coffee shop and their cheap coffee is typically cheaper than the competition by at least a few cents too. So if you're not a consumer with very particular tastes there's no real incentive to get coffee elsewhere when not only is Starbucks going to be cheaper but it's also everywhere and thus probably more convenient for your as well.