I don't know where people got the idea that characters in books a supposed to be likable. Books are not in the business of creating merely likeable characters with whom you can have some simple identification with. Books are in the business of crating great stories that make you're brain go ahhbdgbdmerhbergurhbudgerbudbaaarr.
Human existence is temporary and all the knowledge of the universe we acquire will in time be forgotten because there will be no humans left to benefit from any of the stuff we learned. And yet, this doesn't invalidate scientific exploration to me. We seek to understand the universe because it makes our lives better and more rich. Similarly, we tell stories (and think about why and how to tell stories) because it makes human existence richer. Made-up stories matter. They bring us pleasure and solace and nurture empathy by letting us see the world through others' eyes. They also help us to feel unalone, to understand that our grief and joy is shared not just by those around us but by all those who came before us and all those still yet to come.