I’ve always equated this “simulation theory” very directly with what many religious and philosophical belief systems have described, simply using contemporary metaphors for many of the same ideas.
“We are in a simulation” is, to me, exactly what the Gnostics were saying about The Demiurge and the nature of our reality almost two thousand years ago. Not to mention a lot of the core beliefs of Vedanta, Buddhism, and other systems.
Even the Christian notions of Heaven/hell/purgatory, to me, speak to “there are other levels of the stack” in simulation terms. Pythagoras and his group, the real beginnings of Western philosophy, upon which Plato and Plotinus were built, believed in reincarnation. Isn’t reincarnation just another way of saying this? This version of you and this universe is not the ultimate reality, there are other levels of the stack?
It’s all the same stuff (IMHO), for many many thousands of years now (probably more than we’ll ever know). I happen to be fairly adherent to this view (if it wasn’t obvious), in full disclosure.
Now, what I will say is, the people who are locked-in to a more literalist view of “we are in a computer simulation,” like an actual computer-computer of some sort? I think they’re missing the mark entirely, at least from what I’ve heard. I know many people don’t connect this stuff to ancient belief systems in the way I personally do, but frankly I think that’s mostly due to their not knowing about them, and wanting to feel they’re actually being original!
Edit: Oh, one addition. I seem to remember that my old school DVD of The Matrix had an accompanying documentary that talks all about the movie’s links to the types of belief systems/philosophies I mentioned. The Matrix was talking about this stuff in 1999 – from what I remember, that was weeeelll before all this talk of “simulation theory” was starting to really pick up in more mainstream conversation. The Wachowski sisters kinda had this angle covered!