but they don't value it at zero. if they did they wouldn't pirate it in the first place.
pirating takes time (which is valuable) and storage on a hard disk, which has a cost. so any pirater is valuing it on some level.
as for the photoshop example, again you are attempting to rationalize a crime. Companies already provide subsidized software for students so that they can gain familiarity with it prior to entering the workforce