What I understand is the folloeing: If this works so well, why didn't we have good video generation much earlier? After diffusion models were seen to work the most obvious thing to do was to generate the next frame based on previous framrs but... it took 1-2 years for good video models to appear. For example compare Sora generating minecraft video versus this method generating minecraft video. Say in both cases the player is standing on a meadow with fee inputs and watching some pigs. In the Sora video you'd expect the typical glitched to appear, like erratic, sliding movement, overlapping legs, multiplication of pigs etc. Would these glitches not appear in the GameNGen video? Why?