I agree that money cannot buy happiness. If you have lots of money and can do everything related with money, but if you don`t have your favorite people near, you won`t be happy. Nowadays, some people who were poor and get rich sometimes change there moods, and wish of wealth blinds them. Sometimes there favorite people are very far from them when they discover that they have done many things wrong. In this situation money is only paper and it can not help you.
If people live forever in the world this would not change anything with people. Rich get richer and poor get poorer and it would be a world problem.