That logic might work down to about the size of cells, but smaller than that, that logic no longer applies. It's easily possible to write a college thesis paper on why that is but highly summarized its that quantum mechanics is just too random and odd plus the fact that if you're trying to simulate big things too, accuracy errors will render your attempts fruitless. This already happens in US2 for much larger objects, and though it might be possible to rewire some things to allow better simulation of small objects, I feel if we're still going to simulate planet's, stars, star systems and even galaxies, simulating quantum mechanics is unfortunately just not feasible.