Earlier quoted context omitted.
Does AGI must needs to be brain-like?
The human brain is the only thing we can conclusively say does run a general intelligence, so, its the level of complexity at which we can say confidently that its just a software/architecture problem. There may be (almost certainly is) a more optimized way a general intelligence could be implemented, but we can't confidentally say what that requires.
That's because we define "general intelligence" circularly as "something the human brain does."