With the amount of people who get manipulated with sales and other tactics I don't think we can argue that humanity is composed of rational economic actors. There are some rational economic actors, but the vast majority probably isn't acting rationally with regards to their economics. And that's okay, because humans aren't rational beings first and foremost. We're primarily emotional beings. We make most of our decisions based on emotions, then we may try to rationalize our choice.
It takes a lot of effort to be rational about things.
Holy hell, if some fairly rational person got such a book and did their research on who needs to be written down the world would probably look a lot different in a short amount of time.