You’re forgetting something with the idea of the “possibilities” though. The possibilities don’t look for an outcome in which the Earth survives. It’s all about creating a possibility that the life which exists on the Earth (Humanity) is given the chance to continue living beyond the end of the Earth.
The Earth is done for. The whole while Kagari is laboring away, the Earth doesn’t have enough Aurora left to successfully “reboot” life. If a reboot happens, all life dies. This is what Kagari is trying to prevent; this is what the possibility she strives for creates. A possibility for humanity to pursue another future, a new home, where they can continue to thrive and prosper. Somewhere that they can continue to live, love, create, destroy, and all of the other things that make life wonderful.
<15511> The ideal memory for Kagari...
<15512> Wouldn't that be the will and the power to carve out a new future?
<15513> Something humanity gave up on.
<15514> Something the people lost sight of when they started caring for the planet.
<15515> Even if it means devouring our Mother Earth...
<15516> We have to expand.
<15517> Because...
<15518> Kagari's expression is so kind.
<15519> Because...she looks like a mother watching her children go off into the world.