One of Aaronson's arguments in the article boils down to the idea that running a full universe simulation (without cheating) on a universe with the same physics as ours may just not be possible computationally; it seems physically plausible that you need a universe to compute a universe.
If that's true, then the simulators would need to be running in a different kind of universe than ours... in which case "ancestor simulation" doesn't really make sense.
If that's true, then the simulators would need to be running in a different kind of universe than ours... in which case "ancestor simulation" doesn't really make sense.