I think one of the biggest barriers is that the human brain isn't running on binary code, and attempting to replicate it on our current technology model is doomed to encounter emulation issues.
That’s a “hideously complicated, and not something we’ll be able to accomplish for a long time” argument, which I happily concede may be the case.
I see a very very large gulf between:
“Impossible in all scenarios” and “totally impractical with current technology”.
I was refuting only the former argument.