I am very suspicious of people who say they enter Wall Street to save the world.

That said, I also believe most charity events are very economically inefficient. Rather than get a dozen musicians together for a discounted concert at a small concert hall, wouldn't it be more efficient to ask them all to donate one days worth of sales from performing at arenas?

Rather than get a hundred bankers together for a $250/head dinner, wouldn't it be more efficient to ask them to donate what they'd make in 2 hours? (Although the dinner does have social purposes)

You can like Warren Buffett or hate him, but the best thing he can do for society is earn money and then efficiently give it away to solve big problems. That would be much better than him working full time for the peace corps, or a non-profit.