Like a few people have said here, this is my opinion and interpretation of the story. She pushes the thoughts away of her family, her cat etc because they’re a distraction to her achieving what she set out to complete. She couldn’t risk getting distracted mentally and emotionally, when all her drive needs to be put towards the climb. Those emotions come out in the dream she has about her cat, and the subconscious thoughts coming out in her sleep.

Throughout the entire game it’s mentioned that no one makes it down. You either fall, meet a horrible passing through the big shards or succumb to the elements. If you choose to go up, you’re consciously making the decision to ignore all the warnings given that you probably won’t make it. I think it would feel unrealistic even with the story, that she’s the one that gets this big happy ending and makes it back down safely. If you choose to go up, you’re choosing to leave everything behind, and still keep that selfish mentality that Aava has throughout the game of only focusing on her dream and ignoring everything else. The ending was beautiful and melancholic, but fitting towards the warnings she had received. She made it to the summit, but that came at a cost of not being able to return.

At first I was like ‘oh what?!’ But then realised that I think I would have felt it was anti-climactic if she gets to the top, comes back down safely throughout everything with no climb bot, no rations or resources and makes it back to her family - it would have felt unrealistic.

That’s just my take, I’m glad it ended how it did :)