The only way most companies can measure people is by the amount of time that they put in. So if one is not at the office it can be very hard for the manager to

The only way most companies can measure people is by the amount of time that they put in. So if one is not at the office it can be very hard for the manager to work out how much people are worth. This is because most managers can't work out what programmers do anyway. So though people who work from home might get twice as much done. They still won't very far up in the organisation. Which demoralises them. Plus if they work as part of a team which works face-2-face, they still spend a lot of time working out what's happened at work.