Yes, this is where Carmack's optimism goes awry. He says: "...as soon as you’re at the point where you have the equivalent of a toddler—something that is a being, it’s conscious, it’s not Einstein, it can’t even do multiplication—if you’ve got a creature that can learn, you can interact with and teach it things on some level."
He's wrong. There is currently no practical way to produce a software system that possesses the ability for human thought, reasoning, and motivation without that system possessing uniquely human (let alone organic) properties: the biological and chemical makeup, plus the physical characteristics, of a human, and the ability to process using human senses. (Hint: a neural net processing video images is a mere shadow of how a human processes things with their senses of sight, sound, and touch.)
Carmack thinks humans can be reliably reduced to spherical cows in a vacuum, but that only holds true on paper. A real human being is not merely a meat machine: we are driven largely by emotions and physical desires, none of which exist in a computer except through elaborate simulation thereof.
Now, I'm sure over the next couple of decades we will make huge strides in mimicking a human being's ability to learn, i.e. creating ever more complex LLMs and AI models that act increasingly more humanlike, but they will be nothing but more and more elaborate parlor tricks which, when prodded just the right way, will fail completely, revealing that they were never human at all. They will be like Avatars (from the movie): sophisticated simulacra that rely on elaborate behind-the-scenes support systems, without which they are useless.