I think a slightly sturdier argument is that we live in an unbelievably computationally expensive universe, and we really don't need to. We could easily be supplied with a far, far grainier simulation and never know the difference. If you're interested in humans, you'd certainly take running many orders of magnitude more simulations, over running a single, imperceptibly more accurate simulation, far slower.

There are two obvious answers to this criticism: the first is to raise the possibility that the top level universe has so much computing power that they simply don't care. However, if we're imagining a top level universe so vastly different from our own, the anthropic argument behind the Bostrom hypothesis sort of falls apart. We need to start looking at confidence distributions over simulating universes, and I don't know of a good way to do that.

The other answer is that we are living in a much grainier simulation, and either there are super-intelligent demons flitting around between ticks of the world clock, falsifying the results of physics experiments and making smoke detectors work, or that there is a global conspiracy of some kind, orchestrated by the simulators, to which most of science is party, to convince the bulk of the population that we are living in a more computationally expensive universe. From that perspective, the Simulation Argument starts to look more like some hybrid of solipsism and a conspiracy theory, and seems substantially less convincing.