I would question that you understood the message of Atlas Shrugged.
Ayn Rand wrote a separate small book about selfishness. It is a more formal treaty, and she did not write it easy to read. But her message is clear that acting in our best interest is the basic instinct of all living creatures. We can gain more by working with others than alone. Therefore, collaboration with others is in our most selfish interest.
In my opinion, Ayn Rand wrote Atlas Shrugged for the audience not sophisticated enough to understand her more formal writings. Her goal was to show examples for readers not trained in abstract thinking. She did not aspire to be a literary writer.