Why does Starbucks stand huddling yet alone?

Why doesn’t it have its Pepsi and its RC Cola? Its Burger King and its Carl’s Jr_? Its Adidas and its Rebook? Everyone likes to dismiss it as overpriced McCoffee but if so, why haven’t competitors of remotely comparable size and ambition sprung up in its obviously profitable and still rather vacant niche — the third place ^WPplace? Why is it instead that it has mushroomed globally to the point of cannibalization and watering down? The closest thing I know of a competitor is — and I’m surely biased by being in Mexico — Mexican Punta del Cielo. Though it at least gets the basic idea right and is at least as designed as Starbucks (a crucial point), it is still puny (20 stores) and not particularly innovative. So, again, why does Starbucks stand alone?