You just answer your question. It's because they are living in a country with good economy. People who lives in a poor country tends to think what will they eat for the whole day first, so how can they care about bitcoin when they can't afford even the basic necessity of life? and that's make me sad. The fact that you want to become successful yet you don't have any means. I hope there is an existing group that will let them lend some bitcoins to start with then they will pay it one day ..