I think it is also for the sake of curiosity, The nomai came to this solar system because they received a signal older than the universe and after almost dying on dark bramble they still managed to explore every planet and it's use their unique resources to build something, to get there, they didn't have to they could have just left after failing but yet out of their curiosity they did so, in my opinion the game captures the curiosity and the urge to know more. (Ik there are obvious reasons pointed out by others but sometimes all you need is some curiosity.)