The only purpose aiding others has is to ultimately make us feel better about ourselves, the thought of a relieved neighbor doesn't even cross your conscience because the sole reason you're committing a good deed is to boost your self-worth and expect something to gain in return. If the law of survival dictated your lives, you'd all prioritize your own lives over the others' and no one would bat an eye whether the situation grows dire or not. Everyone is selfish to a certain degree, it's only those who haven't come to terms with it that are out of the norm.