There is a recent article in Erkenntnis that discusses termination risks related to the simulation hypothesis . That is, if we are living in a computer simulation, are there risks that might suddenly cause the simulation to end? The author proposes that there are risks:
The problem with this reasoning is that any computation performed in a simulation must ultimately be supported by computation on the basement level. The computing constraints and the objectives of the simulators on the basement level, therefore, put a limit on the amount of nesting that can occur.8 It is partly for this reason that ancestor simulations entail a termination risk to those that create them. A similar risk is mentioned by Bostrom (2003b, 253), who writes:
One consideration that counts against the multi-level hypothesis is that the computational cost for the basement-level simulators would be very great. Simulating even a single posthuman civilization might be prohibitively expensive. If so, then we should expect our simulation to be terminated when we are about to become posthuman.
I don't understand how a simulation is limited on the nesting that can occur, and therefore the conclusion that there is a termination risk does not follow.
For instance, my thought is that if the universe is already "exactly" simulated ("outside" of our time), then re-arranging components (building a computer, etc) inside the simulation to create a sub-simulation doesn't change anything in terms of resources used.
Question: How is it possible that there is a limit on the amount of nesting that can occur inside the simulation (the simulation of "the simulation hypothesis")?
 Greene, Preston. "The Termination Risks of Simulation Science." Erkenntnis, online https://link.springer.com/article/10.1007/s10670-018-0037-1