Starbucks has thoroughly saturated most cities in the US, and many foreign cities, to the point that pointing out how many Starbucks there are is a
cliche. However, the facts are astounding. In several places in
New York City, one or more additional Starbucks are visible from the windows of other Starbucks. One corner actually has three on it. They have even attempted to tap into the hip-chic
Soho coffee market by opening a coffee store that doesn't actually have a
sign anywhere admitting it's a Starbucks.
There are so many of them because Starbucks is a notorious practitioner of the practice of Block Busting, a practice where national chain retailers draw on their vast corporate resources to descend upon an area and open up enough stores to saturate the market, even to the point where there are so many locations that individual ones aren't even profitable, in order to drive out any competing operations, especially independent 'mom and pop' ones. Then once the competition is driven into bankruptcy, and the chain has obtained near monopoly status over the market in a given area, they begin closing locations to make the operation as a whole obscenely profitable - leaving the community bereft of its local business, dealing with a near monopoly in the sector in question, and with a bunch of vacant storefronts. It would seem that Starbucks is still in saturation mode and hasn't reached the stage of closing redundant locations yet, for they are still opening locations and there are still a few independent coffee houses that haven't been crushed.