I like the ancestor simulation theory and it's really fun to think about. But I don't understand why humans specifically would be the thing to get simulated. Couldn't we just be a bi-product of a universe created to simulate something else? I mean imagine you wanted to simulate a universe -- given enough computing resources you could simulate a universe's worth of atoms, and humans might just be an accidental artifac…
I even think it is more likely that we are not the focus. If I wanted to study humans, I'd just create some and watch them do, I would not bother with simulating evolution, or alternatively burying fossils and creating a whole phylogenetic tree. It is very likely that what we consider important and what this simulation is supposed to be studying are going to be totally disjoint.
But what if it were the "easy" way of creating humans?