Almost nobody works as long as they think they do. They're at work but they're not doing some kind of superhuman 100% productivity blast for 8 hours a day, 5 days a week. Most people have up and down days where they get a lot or a little done; and it averages out. Not to mention they have to prep for and attend meetings, take breaks to eat and so on. Working longer hours just pushes most people into the zone of diminishing returns.