There are non-doomsday possibilities for AGI. Imagine a super-intelligent AI that was built from the start to value humanity and our way of life, and from there it chooses to protect us and enable us all to do what we want more. (Of course, this could go in dystopian directions, but even those are better than extinction.) A super-intelligent AI that is built to value humans could decide to "uplift" humans' intelligence to be able to keep up with it in places that humans desire to keep up with it.
If we can figure out decision theory and how our values work, then when we figure out AI, we can hopefully build it to be aligned with our values from the start, instead of blindly hoping it happens to play nice with us instead of brushing us off like ants.
If we can figure out decision theory and how our values work, then when we figure out AI, we can hopefully build it to be aligned with our values from the start, instead of blindly hoping it happens to play nice with us instead of brushing us off like ants.