We assume that we'll be able to replicate human level intelligence because we'll eventually be able to replicate the physical characteristics of the brain (thou

We assume that we'll be able to replicate human level intelligence because we'll eventually be able to replicate the physical characteristics of the brain (though neuroscientists seem to think we're not going to be able to do this for a very long time). Superhuman intelligence, though - that's making the assumption that there exists a much more efficient structure for intelligence and that we (or human intelligence level AIs) will be able to figure it out. So returning to your Wright brothers example, it's more like saying: "It took birds 3.5B years to fly, but the Wright brothers engineered another way. It seems likely that we'll soon be able to manufacture even more efficient wings small enough to wear on our clothes that will enable us to glide for hundreds of feet with only a running start."