It's like saying that we can't simulate a computer in a Turing machine because a Turing machine doesn't have a USB port to connect a mouse. Change the perspetive considering that the mouse movements are inputs and everything works. Same idea
I don't follow the analogy.
Simulating a brain with its neurons cannot achieve the desired outcome. A perfect digital brain won’t do anything.
The brain is a part of a much larger system. We don’t really have a clue how to model these things, even theoretically. It’s vastly more complex than neurons.
Modeling at this level may be practical in retina at some point but modeling the entire CNS for pragmatic gains for Alzheimer’s disease research is not going to work.
And embodiment is critical. The brain is not a Cartesian input-to-output machine. It is almost the opposite. See the “enactivist” philosophy of cognition (Noe, Velera, Maturana).
(I also worked on the EU Human Brain Project with Markram and others; also on several similar NIH programs. )
Accurate understanding of 'normal' brain behaviour might lead to increased understanding of brain diseases. Thats why alzheimers was mentioned. But more importantly, if our understanding of the brain becomes good enough, we might be able to make a neural net understand our thoughts if we can adapt to it.