Wouldn't having showers at work be useful in encouraging staff to participate in sporting activities other than cycling? What about folks who might want to go running, jogging, do other active stuff at lunchtime?
Having facilities (i.e. a shower, lockers etc) could remove potential barriers to participation in activity. Some folks might well think cycling to work will work up a sweat. That could be a barrier to them giving up the car ('why cycle and get all sweaty when you can stay perfectly groomed...and sit in traffic...you can go to the gym to get fit').
Much as I wish we were, we don't live in a country with an established cycling culture. Some colleagues regard me as some form of hero for cycling to work in poor weather. Covering my short commute (6 miles each way) is deemed a near-awesome feat. I've even been asked if I don't drive...