I believe in abundance. People who have abundance do not mind to share. The issue is on the definition of abundance. Abundance is in the mind of each person. Many people feel full with some amount of money and share whatever they have with others, and some people, it does not matter what they have, they always feel they do not have enough and they cannot help others or share becauase they feel that they are in constant need.
I know people who move into beigger houses and still fill it with things they buy, they dont get rid of anything, and then need a bigger house and they still fill the new house.
People who feel well and satisfied will share. It does not matter how much they have, but how much they feel they have.