I don't buy that at all. One ethical way is to marry someone random who later becomes a billionnaire. Another is to eg create Bitcoin. And I suspect there are ethical ways to create a business that earns a whole lot of money.
What unethical things did Yvon Chouinard do to get his billions? Chuck Feeney? What about Mackenzie Scott (formerly Bezos)? Hansjörg Wyss? Craig Newmark of Craigslist?
Being a billionaire itself is unethical. They are excessively greedy to the point of evil. If they weren't they would have stopped hoarding wealth hundreds of millions of dollars sooner.
If I had enough food to feed a hundred thousand people for the rest of their lives, more than anyone could ever eat in thousands of lifetimes, and I kept hoarding more and more food while people were starving you would ask what the fuck is wrong with me, there's no way I'll ever need all that food. I would rightly be called obsessive, greedy, and a sociopath. Add one layer of abstraction and we hold these monsters up as heroes.
- Mackenzie Bezos gave away $26 billion, more than half of her net worth, in the past 6 years. I'm sure she'll continue.
It's not exactly easy to spend so much money _meaningfully_. "Giving it away" sounds simple, but really it's a lot of hard work.
You seem extremely attached to your point of view that all the billionnaires are bad people and that you're a good person. I have a negative visceral reaction to people who loudly proclaim their own moral superiority. I don't think all the billionnaires are that bad, and tbh I have trouble believing you're such good a person. How much have you given to charity?
If you really want to know, I give away more than 10% of my income every year to charity. In just the past decade I've given away about 20% of my net worth, and I'm not even close to set for life. That's more than all but a few billionaires will give away in their lifetimes, and I promise you that I need that 20% much more than any billionaire needs 90% of theirs. If I lose my job I'm fucked, if they never make another dollar they can live thousands of lifetimes without changing their standard of living in any meaningful way.
Does that make me a good person? No. It absolutely makes them bad people though.
Giving away money doesn't make you a good person, but hoarding it makes you a bad person.