And China has more than twice as many internet users as the United States. However, I'm pretty sure the American users spend more money per capita and that it's not an accident that most YC startups target them first.
My point was (fairly obviously) an analogy. However, almost all startups have one of two business models: either they sell things to their customers, or they sell advertising space to people who want to sell things to their customers. Both require customers who spend money.