It's not at all clear that AGI is technically feasible. Human brains exist but we have only a shallow understanding of how they work.
Even if we assume for the sake of argument that AGI is possible, there's no scientific basis to assume that will make humanity obsolete. For all we know there could be fundamental limits on cognition. A hypothetical AGI might be no smarter than humans, or might be unable to leverage it's intelligence in ways that impact us.
Nuclear weapons and malware can cause damage but there's no conceivable scenario where they actually make us extinct.
Even if we assume for the sake of argument that AGI is possible, there's no scientific basis to assume that will make humanity obsolete. For all we know there could be fundamental limits on cognition. A hypothetical AGI might be no smarter than humans, or might be unable to leverage it's intelligence in ways that impact us.
Nuclear weapons and malware can cause damage but there's no conceivable scenario where they actually make us extinct.