Somewhere around the time when there is three humans left on the planet, two of them will unite together to kill the third one. For a brief moment after the third one is dead the last two humans will be united in not knowing which one will attack the other one first.
I came here to write something along the lines of this.
And the last couple of humans will spend an awul lot of time reassuring each other that circumstances beyond their control forced them to react like they did and there was no way they could have done anything differently.
Let’s face it, while there were/are promising moments, we as a species are a failed experiment.