Even with the most advanced GPU-accelerated simulation packages, if you want to get to molecular-level detail and nanosecond-level dynamics (both of which are required for drug interaction), the compute time required for an accurate simulation of even a microscopic volume (say a cubic micron) is on the order of the heat death of the Sun. We’re so far from this it’s laughable. The best simulator is still the real atoms of the real world - we just need more reliable ways to control and measure them.