Unfortunately I think the answer to "why keep working if you're already rich beyond the dreams of avarice" is "because it means you can keep being ultra-rich an

Unfortunately I think the answer to "why keep working if you're already rich beyond the dreams of avarice" is "because it means you can keep being ultra-rich and powerful and famous". All your material desires will be met regardless, but you won't get to feel as important if you stop working.