When we talk about after scarcity, we're talking about an endlessly sharable amount of wealth. (Not in a technical sense, of course)

Then the super-rich will start sharing their wealth, because if they don't, their competitors will do it first and take all the fame. It is not from the benevolence of the super-rich, the butcher, the brewer, or the baker that we expect our dinner, but from their regard to their own interest.