And if she were acting in her own rational self-interest, she would do the same, since her well-being (and in fact, as neatly illustrated in the comic, her very life) depends on the well-being of the group.

This assumes perfect foresight. As can be seen from the history of robber barons and the legacy they left, it generally did work out for most of them, so they were correct in their choices focusing on self-interest. Not since the French revolution has any significant number of rich assholes faced significant consequences for their choices in placing their personal welfare above the group.