There are myriad ways that humans tend to make bad decisions in the course of modern life. Psychology and evolutionary biology currently provide the best answer to "why".
If you want to understand yourself well enough to be able to avoid having marketers and advertisers make your most important life choices for you, or want to raise your children to think critically about statements they hear even when it means overcoming confirmation bias, or want to think about how to help society escape detrimental Nash equilibria that lead catastrophic global warming, a deep and accurate understanding of human behavior seems to me to be clearly better than simply operating under the wildly simplistic assumption that people always behave rationally in the pursuit of well defined goals.
I think it’s wrong to assume that evolutionary psychology and sociology are mutually exclusive.
The explanation is that Homo economicus, the economic optimizing agent, is a leaky abstraction on top of a killer ape. In the modern environment, it's easy to forget that our brains did not actually evolve to deal with money, let alone the high-tech infrastructure of a modern corporation. They evolved to dominate other apes on the African savanna.
But evolution does not document its handiwork. Our genes did not give our brains an explanation of game theory and the evolutionary utility function. They gave our brains a propensity to seek power and to feel pleasure when successfully wielding that power to hurt other people. That this behavior was adaptive in the ancestral environment is a historical fact, not represented anywhere in our neurons.
So yes, it's not about productivity, it's not about profit. It is, as Orwell put it, about the end goal of a boot trampling a human face, forever. That is the default fate of humanity unless that fate is actively and continually opposed.