I think it's a reasonable barrier. Ant nests are fairly capable as reactive systems but limited by the inflexibility of the stigmergic control systems they're r

I think it's a reasonable barrier. Ant nests are fairly capable as reactive systems but limited by the inflexibility of the stigmergic control systems they're running on. I doubt such a substrate could implement true intelligence. As for humans - "locked in" people are a special case, their outputs have been entirely disconnected (unlike dolphins). But we are pretty close to having the tech to reconnect them. Again, humans find a way around it. Exception: there are humans who IMO do not qualify as people. That is, no measurement even with a mind-reading machine would call them sapient - they get grandfathered in because they share a species with us