That's not true... There are a lot of people who are millionaires or billionaires and they have a good family.
It depends on the characteristic of people. Of course there might be rich people who act like that but this is not the majority.
Zuckerberg and Gate are some examples of humble rich people.
I would say there is definitely a difference in people who became rich themselves, and the ones who inherited wealth from their family. If you had to work yourself for everything you will value it much higher and be more humble. I wouldn't call Zuckerberg humble. Bill Gates and his wife are more humble as they gave so much more money away and engage in a lot of good work around the world. Like with Polio in Africa.