I think there is no way 996 work culture improves productivity. Working that long only causes burn out which makes developers slower and more prone to mistakes,

I think there is no way 996 work culture improves productivity. Working that long only causes burn out which makes developers slower and more prone to mistakes, and with more mistakes leads to more effort devoted towards fixing those mistakes. Personally, my productivity varies greatly depending on my mental state, days when I am feeling fresh/sharp/motivated I can accomplish more in a few hours than I could over days burnt out, and the resulting code is more resilient and thought out than I anything I could produce burnt out. When I am burn out, my mind is foggy and less able to reason about various branches of the program and I am way less motivated. IMO like other posters have stated, 996 culture is less about productivity and more keeping up appearances with management. In China/SK/Japan you don't leave until your boss leaves, even if your work is done, so you will see people staying late a work shopping online or playing video games. The more the office becomes your home the less productive of an environment it becomes.