People/Companies copyright their work, so that they can earn money by selling their work, and not allowing anyone to copy their work (probably, unless they pay some royalty). They have spent their time and effort, and in return they should get some thing, and Copyright is meant for that only.
Suppose, if a person/company has done some work, which is very valuable to the society, and they will not get even single paisa from that by selling or by any other way. In that case, if they release their work for free for others to use, then it would be very valuable to the society, and they get enough fame, and publicity for that. But, still many people/companies are not doing that. Probably, the main reason is greed, or jealousy. They don't want others to enjoy some good thing for free.
If a person/organization is working for society, and not for money, and their vision is completely different, then, still what is the reason for holding copyright? If by releasing that work for free, if it improves the society, why are they not releasing it?
For example, there are few religious organizations, and they have copyright for all the books/audio/video. Nobody is allowed to copy books for free. When I asked one senior person, he said, they need money to develop the organization. If they remove the copyright restriction, then they will not get money to develop the organization.
What is the purpose of that organization? It is to preach religious activities. Their vision is, everyone should understand their philosophy. For that, everyone needs to read these books. And, these books are copyrighted by them, and others are not allowed to copy. So, they are restricting the readers. Is it their vision? For these questions, they give all sorts of random things like, anyone can come here and listen to the preachings for free etc. I feel so irritated with them. They say that, they are here for the propagation of their religious philosophy, but, they don't allow others to do the same.
There are many people/organizations like this. Eventhough, they can fulfill their mission, by releasing their work for free, they are not doing it. Probably, the reason here is, Fame. They want all the fame for that work, and in the process, even if their mission is delayed, they don't have any problem. They don't want to give any credit to anyone else.
People/Companies/Organizations have full right to get as much money as possible from their work. Once, the money stops coming, and if they release it for free, then it would be very useful for the entire society.
After criticizing few organizations, it would be very bad on my part, if I don't name few organizations which are releasing it for free.
Chinnajeeyar Swamy graciously agreed to distribute all his preaching audio/video.
Gita Press sells books for pretty less price, that even if they put the books on public domain, nobody would dare to print for that much less price. Of course, releasing the books on public domain may help the people who read soft copies of the books. Of course, even if you take those books, and create soft copies and distribute it, I don't think they will complain.
Sun, and IBM are the two biggest software companies which open sourced their work. There are many other organizations like Apache, GNU, Mozilla, X.org, FreeDesktop.org, MySql, and many universities in US are helping in opensource software.