I think Bill does try to make sure all his money is well spent though. His foundation doesn't throw money at a problem. They come up with a strategy first for a given problem and execute on that strategy.
Besides the money he had given to the apparatchiks and money wasters of the Global Fund to fight AIDS, TB & Malaria (GFATM) where - as it became public latest last year - up to 2/3 disappeared with mismanagement, corruption and other abuse of funds (administrative fees not included) - I guess nobody is perfect