I understand Gates has also helped in reviving Nuclear power, from reading news on this site and others. Smaller, updated designs that don't face quite the same level of pressure from regulators.

If we assume you are right about billionaire philanthropy being basically ineffectual (I personally agree) there is a line of reasoning that I find explains why adequately. When systems don't have their incentives structured properly, then quite often the unexpected outcomes are stronger than the predicted outcome. Because the input to the system did not properly account for, or change the incentives which drive the dynamics of the system.

Examples about in healthcare, social programs, education... large SWE companies...

There's so little real pressure for results when you're backed by some billionaire's fortune, the existence of the organization is not threatened by non-performance... there's no free market to survive in, the goal is to lose money... the things you are trying to measure are slow signals or mostly qualitative...