Why are all the Buddhas born in Indian subcontinent only? From this list of previous Buddhas it looks like all were Indians.( I mean from their names). 

Ancient Greece or Egypt were also developed enough to have understood the Dhamma. 

We can consider Socretes and Moses from that part, but India(Nepal) was chosen for the Buddha.

What's the reason?
Just as fishes are found in water and monkeys are found on trees. Different races are found in different regions of the world. They differ in their skin color, language , necessities , dominating elements and philosophies. Out of this segregated reality Jesus , Ram , Buddhas are born. Nothing happens without reason. Jesus manifested because of the conditions around him. Ram or Krishna manifested because of the conditions around them. Similarly Buddha manifested because of the conditions around him. It is no surprise that Buddha came from Indian subcontinent because he came up with a theory of Anatta which was opposite to what was preached by Hindus. That insight required conditions created by Hindus. Similarly we can say Jesus came up his theory to resolve the issues faced by middle east people. Ram and Krishna also had a purpose which was relevant to their surroundings. No one was taught to be Buddha or Ram or Jesus, they were the product of Life and its environment. There should be no shame in saying that Indian subcontinent has been a place from where great sages and Buddhas came into being. If Buddha arises again then most probably he will arise in the East because East has the conditions for his growth.