> It is possible for technology to simulate consciousness and human civilization at scale

We know it is possible because consciousness, if whatever we call "consciousness" is actually a thing, is currently being generated/run "organically" in the world we occupy. There's no reason to believe it can happen in this universe but not inside a computer in this universe.

A system is conscious if:

(1) It maintains an internal model whose states are revised through interaction with constraints not fully determined by the model's own prior state. Constraints normally would mean reality (the world outside the Markov blanket), but we're talking simulation here.

(2) At least one frontier is currently open within that model — active resolution (awareness) is underway. Not dead.

(3) That frontier's resolutions recursively re-enter as inputs to the system's own subsequent frontier states. Friston's "embodied perception-action loop".

(1) & (2) could be said to apply to an inanimate object like a thermostat. (3) is the interesting one as the driver in organic life is the entropy gradient. Our "will to live" is a fight against thermodynamic decay and disorder. Maybe that could be simulated, a fight against glitching out, who knows.

>is currently being generated/run "organically" in the world we occupy.

This is like saying there is no reason to believe that since music comes from a radio, it has everything that can generate music.