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?
$5b wouldn’t do much in the grand scheme of things but it would make me the wealthiest person in my city 10x over. I’d fund progressive campaigns across the board to stack the legislate with like-minded people and then work on building my local community and hope that it has leeching effects on the surrounding area, state(s), country.
I feel like we have very different beliefs on what “grand scheme of things” means because I don’t believe $5b will make an immediate difference right away for most people, but you can implement small things that will create ripple effects that greatly change the grand scheme of things for the future.
There are billionaires out there right now who are investing their money in trying to solve the world’s problems. Bill Gates has given away $60 billion dollars of his own money so far through his foundation as of the end of last year.
That money goes further being spent on developing nations as opposed to the USA so people don’t seem to notice. The WHO is trying to eliminate malaria by 2050 and we’ve gone from there being ~1,000,000 deaths per year in 2000 to ~300,000 cases per year in 2024.