It's easy to explain. The level of detail and quality is far too high for real time processing like it is needed in a 3d game where you can move around freely. Most of my renders (and that is just 1 still image) take between 10 and 45 minutes. In a 3d game you need at least 30 frames per second.why they dont make 3d games with models like this ? let me bet, it need to much time