Also, you could compare philanthropy with the "foreign aid" that western countries give to poorer ones for decades now. Did it help? In many cases, it made things worse, because the money did not help the people to help themselves, but made them addicted to the aid.
The point is also that philanthropy -- as it might silence the own conscience -- is often the overflow of the overflow. We give, because we have more than we need and than we give what we need least. But what people really need, is not somebody that throws pennies in your hat, so you can buy some old bread -- but what they really need, are equal chances -- to be able to visit the same universities, to have the same jobs and to earn the same money as other people with the same talents.
You might argue: But Bill also fought his way from "rags to riches" -- no, that is not right. Bill already was born in a well being family and visiting visited Harvard College. With such a background, it is much easier to come from rich to riches, as if you come from Uganda slums (or even Harlem).