The premise of your question is the world model in which humans are given short lifespans to do something, replicate themselves and vanish from existence. I won

The premise of your question is the world model in which humans are given short lifespans to do something, replicate themselves and vanish from existence. I won't debate this hypothesis, but I want us to agree that this model isn't necessarily correct. In the first world model, wasting energy and time is indeed suboptimal and humans indeed must focus on survival. In the second world model, curing the cancer is about as valuable as extending the lifetime of cars to thousands of years, while figuring out how the world works is the number one priority. I believe that humans intuitively lean towards the second model, and although they can't say it out loud, they do things that are optimal in that model. Thinking about chess won't extend anyone's lifetime, but it might reveal something important about the underlying principles of our world or of our thinking process and we secretly recognize that making that little discovery would be worth everything.