Can we really refer to ancient technology like aqueducts as innovation? I mean, they were in use in the 3rd century BC.
Yes, of course: the men of the day saw a problem and then innovated to overcome it. Innovation is a timeless human attribute and capability -- which is why we need more people in the world to innovate and not less (per the depop psychopaths). There is are no "limits to growth" in this age.