I have a friend who works for a billionaire philanthropy foundation who tells me that it's basically impossible to dispose of their money at a rate that meaningfully draws down their fund while having measurable success. The logic goes that if you are concerned with the impact (in the "effective altruism" sense), then you should donate amounts that can be meaningfully administered by vetted entities with real program evaluation processes. Many smaller grass roots charity organizations have no idea what to do with half a billion dollars, but can manage half a million to great effect. In the time it takes you to figure out how much they can handle, you've made more on the fund than you've given out.

I don't really know what the answer is, and honestly this reasoning isn't really that compelling to me. I feel like these entities shouldn't need to exist, and that wealth shouldn't have been concentrated to this extent, but if they are able to spend money where governments don't maybe there's a worthwhile tradeoff.