There are levels of richness. A person that has a million dollar worth of assets is considered rich but some other guy with $10 million is 10 times richer than him and can afford to have many more luxury items than him. Then there are other people that have $100 million in their accounts.
Long story short, a rich person wants only one thing: to get even richer.
The mission only ends when he becomes as rich as Warren Buffett or Elon Musk.
The mission doesn't even end after that because do you see any of them stopping and enjoying life? No, they still continue doing what they do and I don't really understand what's the point of not having fun when you have all the money. I think that rich people develop money addiction and it becomes a mental illness because when you have so much money that you can't even spent and still don't have fun, that's not normal.
Who is not addicted to money? Are we and the poor addicted to money? I bet everyone is addicted to money, not just the richest billionaires in the world.
Honestly, none of us are rich, none of us have ever experienced the life of rich people so we cannot know what they think and what they want. But if I were to speculate, I think the ambition of the rich does not stop at making a lot of money or becoming rich to enjoy life. Like Gate, he was once the richest man and with his wealth, he could live a life without worries. Or like Elon or Trump, they are billionaires and have everything that others dream of. But it seems they're not stopping there, Gates is spending money on research and charity, while Elon and Trump are looking to get involved in politics... all showing that they have bigger ambitions beyond money.
I can't put it into words but as many people say, billionaires have more eccentric ambitions than ordinary people like us who are just after money.