What is the point of trying to make life better for all people?

For example, imagine that I am, for some reason, deeply invested in the concept of world peace, and I spend my entire life working to try to make it happen, and I accomplish it. (For the sake of this argument I am omitting the question of how I might accomplish it and instead only focusing on why it is valuable.) So I have now ensured that all people are at peace with each other. According to my philosophy, my life has been a success.<br><br>But the people who are at peace still have to die. Maybe they enjoy their lives before they die, that is not what my question is about. Whatever happens in their lives, they have to die. Beyond that, from the perspective of the universe as a whole, their lives are completely meaningless in the grand scheme. Our sun will eventually go supernova in a few billion years, and even after that, the universe will eventually collapse in on itself or experience heat death. So, not only are all my accomplishments temporary, they are also irrelevant.<br><br>This raises the question of why I pursued the goal of world peace in the first place. What is the ultimate telos of my actions? In other words, why did I pursue this goal, and what is the purpose of my pursuit, in a universe in which death and destruction are inevitable? This perspective completely undermines my motivation to seek the betterment of mankind, and indeed, to do any action at all.<br><br>The same line of thinking can be applied to any possible action. No matter what I do, I will eventually die, and no matter what humanity does, it will eventually go extinct, along with the rest of the universe.<br><br>What reason is there, then, to do anything?