Exactly. We are beings of atoms and matter. If you want to believe in some immaterial soul, fine. But if you're a materialist, then everything we are is atoms. We know atoms in one configuration can produce true intelligence. And there are likely many possible arrangements of atoms that can reproduce this effect. And since artificial minds are not subject to most of the constraints of biological minds, an artificial superhuman intelligence should be possible. Hell, even if biology was the only way to make it possible, you could always build an artificial biological brain and just make it a lot bigger than a human one. Even if human neurology really is the limit of what this universe allows for in terms of intelligence, we could best it by just making a bigger one.

We are far from knowing that true intelligence is possible with the computing paradigm as we know it, and indeed, if it's even possible to do outside of biological systems. So it does require a revolutionary breakthrough in computer science and/or computer engineering.