Personally, I think Rand was deliberate when she made her characters as they were for the sake of the novel. There were very few "gray-shades" to be found because she wanted to paint a stark contrast between good and evil.
In a civilized, certainly Christian society, we recognize that there are needy among us who require some help. Most of us know this, and are more than willing to offer care. But I question your "human nature" reflections on altruism. In its base form, human nature is to look out for one's own self first, before others. We are social beings, but when pressed into a "your life or mine" situation--especially if I have no connection to you otherwise--my life will come first.
People do move beyond the pure Objectivism expressed in Rand's novels...because our lives are not novels. Once we go out into the real world, with jobs and families, we realize that compromises are sometimes made, particularly when it comes to raising children. But we recognize that AS was a fictional work, it was not meant as gospel! Reasonable people can read Rand and say, "yes, she makes some good points and generally I agree with her," without completely transforming their lives into a model of Francisco D'Anconia.