The question isn't how many simulated observers exist in total (although that's also unknown), but how many of them are like you in some relevant sense, i.e. what to consider "typical".

I also find it hard to believe that humans of any sort would hold special interest to a superintelligence. Do I really have the burden of proof there?

But in any case, I don't think your original idea works. Running a simulation of your ancestors causes your simulated ancestors to be wrong about the DA, but it doesn't cause yourself to be wrong about it.

The whole point is that the simulators want to find themselves in a simulation, and would only discover the truth after disaster has been avoided. It's a way of ensuring that superintelligence does not fulfill the DA.