An interesting economic question is how do the likes of Microsoft stay in business. With the amount of free software do they really offer value for money? Why doesn't every person or company use stuff that's free?
I think the honest answer is that it's the way we have always done it, would people feel the same if they didn't dispatch a regular payment to Microsoft and the like. People feel safe and like the feeling of security, even if the free software can do the same job or even a better job.