I don't think people are like machines. I don't think you get more work done by making them work longer. They just work less efficiently, and to lower quality. I personally spend a lot of time at work daydreaming and mucking about, and then (I think) when the chips are down I accomplish quite a lot in a short time.
Here's another perspective. I had a close friend, let's call him A. He worked stupidly long hours for Japanese investment company. He used to say 'I'll work like crazy for ten years and then I'll retire rich'. He never made it. He told me satellites were beaming information into his head. Last I knew he was in mental hospital.
Do you work long hours? How does what you create relate to how much you work?
discussion of Electronic Arts on metafilter , and a broader discussion about long hours culture on Crooked Timber.