It's all about economics.
What races buy video games?
What continents buy video games?
What countries make video games?
As time progresses, and economies develop, we'll see more diverse lead roles. But when your audience and consumers are white-skinned, and either Caucasian or Asian by a vast, VAST majority...Your going to lean one way.
Should the midde eastern, african, or indian economies develop into powerhouses, I am sure more and more developers will spring out from those areas due to better education, and spur video game development and purchasing power in their territories.
So the simple answer is that we don't see diversity because people that make and buy games are white-skinned, and it's easier to cater to the largest, most profitable audience rather than make your lead character Indian or Middle Eastern and lose out on 90% of your audience.
Back from the dead, I'm afraid.
