That's the question. Suppose you are part of 10%. You are a person with money. You spend 10% of your income to satisfy all your needs. How are you going to spend remaining 90%? Keep in mind that your needs are already satisfied -- you have to spend on something that you won't consume.
But their needs are not already satisfied. Maybe their physiological and security needs, but what about their needs for belonging, esteem and self-actualization? The more likely scenario is they'll spend the remaining 90% trying to fulfill those needs through philanthropy.