2. Because ai doesn't have biological scaling limits. There's nothing particularly special about human level of intelligence.
Big claim since nothing in the known universe has human level intelligence besides humans. It's like holding the original declaration of independence and saying that there is nothing particularly special about this piece of paper.
What do you propose is special about human-level intelligence? If anything, it is in constant struggle with biological and emotional needs. Yes, of course, human brains are amazing, the declaration of independence is great, but the entire human project is the push for progress.
IMHO in the community there aren't any significant objections to the Legg & Hutter definition proposed in that document "Intelligence measures an agent’s ability to achieve goals in a wide range of environments." - perhaps you can tweak the wording some more, but that's the direction implied by people talking about building general intelligence and (at some future point) human-comparable general intelligence; in essence it's about 'wide-coverage' intelligence of being efficient at different purposes and figuring out what is required to be successful for these purposes, as opposed to narrow single-task specific effectiveness; but it's essentially a metric on which one quite reasonably can imagine something being equivalent to or better than the average (or x-th percentile) human.
It's not about the capabilities of unassisted body - I can influence stuff in a volcano without sticking my bare hands in it.