Also, if you permit me to get spiritual for a moment, I believe that it could be theoretically possible to simulate any fully materialist universe, but I'm not convinced consciousness can arise from doing maths. Since I am conscious, this universe must not be simulated, no matter how many simulated worlds actually exist.
[1] I'm assuming that most creatures intelligent enough to understand the concept of simulating a universe will want to try it. But if it takes an entire civilization to do so and that civilization has to choose between, say, spending the energy on simulation running or on food production, it's pretty clear what will happen.
However that doesn't preclude 'my' version of the simulation hypothesis. Imagine you were in a full body VR sim from the moment of birth, that artificial reality would likely simply be reality to you, yet your consciousness would remain. So all that's fundamentally required is some tech to temporarily block all past memories before entering the sim.
Sounds like an interesting concept for a story, if nothing else.