I think an important lesson is, from all comments here, that you can work a lot less and get away with it but you need to excel in areas other than productivity.

What are those areas? Imho: Vision, providing direction, knowing when to be productive at the exact right time, identify well in advance what won't work, identify who is doing the same as you and working together or leveraging that work. Perhaps you can do very little until you finally identify that one core important thing and be praised for those couple of hours. It's a skill as any other.