I have a very hard time believing that hours ~50–130 are as productive as 1-~40 or 50. I’ve been there at startups in the middle of the night, and the best work isn’t happening. People are tired. The myth of endless productivity is just that…a myth. Now, if people came to meetings or work collaboration time prepared, stayed off social media at work, and in general made the most of their working hours, I have no doubt that the best work could be achieved within 40 hours.