Do you know any wealthy people who are still frugal?

I really appreciate the psychology or mentality behind frugality. It's part of my upbringing as my parents were poor. So it's something that will always be part of me. Some of the very rich people I've read about still drive their old car, look at menu prices, and even cut their own hair. Would you still be frugal if you could essentially afford to buy your whole neighbourhood? Do you know anyone like this?

Edit: Wow, thank you all for sharing!! I'm really taken aback by all your inspiring comments!! I loved reading all your incredible stories, so wonderful to see that most people are still very frugal, regardless of how much money they have.