Just as a note - I feel like there's a lack of understanding of how difficult it is to get a billion dollars. It isn't something you can just trip into and I think the concentration of that much wealth really goes against something in most people's approach to the world where generosity increases as you gain more wealth. To capture that much wealth as a business owner you have to be extremely stingy with compensation to those who accompanied you along that path which is not how most people tend to operate - more often people share that wealth and make sure those around them also benefit from the work even if the structure of corporations may technically entitle the owner to 100% of the upside.