I believe anytime you spend $250 million, the results, whether good or bad, should be clearly visible. In this case Gates could have burned the money and there would have been roughly the same results.
So I don't think he would get the "same results" by burning the money.
Can you tell me bad things what the Foundation does?
Some sources on the legitimacy and efficacy of their workings (within global health):
Doyle, C., & Patel, P. (2008). Civil society organisations and global health initiatives: problems of legitimacy. Social Science & Medicine, 66(9), 1928-1938.
Pfeiffer, J. (2003). International NGOs and primary health care in Mozambique: the need for a new model of collaboration. Social Science & Medicine, 56(4), 725-738.
Storeng, K. T. (2014). The GAVI Alliance and the 'Gates approach' to health system strengthening. Global Public Health, 9(8), 865-879.