To elaborate, time is the problem. The number of atoms in the smallest viable cell is actually reasonably small, less than a billion atoms, such that you could

To elaborate, time is the problem. The number of atoms in the smallest viable cell is actually reasonably small, less than a billion atoms, such that you could hope to store it all in memory on a single beefy computer. Meanwhile, you need something like picosecond resolution in the simulation, while you need seconds of simulated time to see interesting macro-level things happen. If you want to see cell division, you're probably talking a minimum of thirty minutes of simulated time.