So what? If it kills us, we're still dead.
> I would argue there are strong complexity-theoretic bottlenecks to computational processes which limit the expressive power of neural networks
Of course there are physics/CS limits to how intelligent something can be in a given volume, but those limits are vastly higher than our own so I don't think they are particularly relevant. For instance, a system which could simulate the brains of a thousand scientists as smart as Einstein a billion times faster than realtime would not violate any rules of physics, even though it is far beyond our current capabilities.