Not only did she understand human nature, but she described it to a T, along with what it would lead to in practice. If you doubt that she predicted what we see today all around us, then you owe it to yourself to read it again. That is, if you really want to understand the current trajectory of American society.
She understood her concept of objectivism pretty well. I’m not saying she’s completely full of ****. There are some things I think are right about objectivism. But the amount of **** she was full of relates a lot to the extent to which objectivism doesn’t map to the practical world. There’s a logical beauty to it, on an individual level, especially as a principle to live your life by. But other people are in the world too. It just doesn’t scale well.