One argument against the "we're probably doomed" conclusion is that the impact of a roughly speaking "intelligent" system -- say, one that can be interpreted as maximizing some utility -- might not be recognizable to us. As an example to instantiate this possibility, if it were evolved to the point that its optimization procedure was as precise as say, the laws of physics, then we might just interpret it as a physical law.

In other words, the whole situation is really evidence that if intelligence evolves highly frequently in space and time, then it probably evolves in a way that renders it eventually undetectable.