This seems needlessly pessimistic. For one thing, sharing and giving resources is innate in humans, we have to have that instinct to at least raise our young and the instinct obviously extends further than that. For another thing, we may be given a lot but if someone produces excess (and in our society we have the ability to produce an abundance of a lot of things) what else are they to do with the excess? Especially if everyone around them is giving their excess away too.