Starbucks found that throughput is sublinear with respect to store size. If you get bigger than a couple cash registers and an espresso machine, the physical wo

Starbucks found that throughput is sublinear with respect to store size. If you get bigger than a couple cash registers and an espresso machine, the physical workflow, customer queueing, etc eat up the gains from making the space bigger. So, if there's a location that can sell enough coffee to justify opening two small cafes, they open up two small cafes. They never open larger cafes that can serve twice as many people, because that costs more than twice as much for the same throughput.