You get to keep only enough to maintain a very modest lifestyle in a low-cost-of-living area, the rest of it has to go towards improving the world in some way.
Edit: Given the previous rules that you must maintain a very modest lifestyle in a low-cost-of-living area, would you rather choose to opt out and not have the money at all?
Great idea! But what happens then? There’d be some fear, but more importantly, a certain vacuum of power. How could you make sure another power-hungry, sociopathic populist wouldn’t rise? Or, again more importantly, make sure people cannot fall into these traps again, which only happens due to a lack of ideology, generalized ignorance and a belief in ‘moral relativism’ (among other issues)?
Btw, Frank Herbert explored this in Dune… it requires a virtually immortal prophet! 😅
Not my problem because I would have to die too.