And many companies do have telecommuting. In fact some companies don't have offices and everyone telecommutes.
While I choose note to telecommute, a lot of other people do where I work. They are just as productive as if they were in the office. Some more so. Someone who telecommutes 2 or more days a week now is unlikely happy to be happy with a 4 day contract. I think flexibility in general should be encouraged. And that includes both telecommuting and various work schedules.