More complicated than what? Quantum physics deal with a different kind of phenomena that seems to be random in nature. Macroscopic physics emerge from micro-wo

More complicated than what? Quantum physics deal with a different kind of phenomena that seems to be random in nature. Macroscopic physics emerge from micro-world, so different scale. If what you are comparing is classical with relativity, Occam only applies to simplest answer that explain all observable reality. Classical didn't explain enough, so it needed to be corrected by a more complex system.