The situation is a bit more complex than that. First, people don't live in the office, so even if you live closer to the workplace, you still spend a non-negligible amount of time preparing and getting there. It can easily amount to more than 30 minutes a day.

And secondly, an office job can be stressful, consuming, in a way that commuting isn't (if done by train or bicycle for instance). So i wouldn't put them all in the same box as time devoted to work.