Until the late 20th century, knowledge was seen as common to all. Copyright existed to give people a window in which to sell new books, etc and make enough money to justify their development and publishing, and then the work was expected to be in the public domain, where all could benefit from it. With the rise of mass media, and corporate ownership of knowledge and works of art, this has changed. Creative works are seen as the property of the companies which develop them. Creators do work-for-hire, and their product is owned by the companies. The fact that companies never die means that companies can own the copyright to something in perpetuity. Current law is inconvenient, since it limits copyright, but the laws have been extended so much now that the copyright ownership is longer than a person's lifetime. I predict perpetual copyright will be coming soon enough. If not, ad-hoc extensions to copyright terms when works are about to revert to the public domain will be more and more common.
Companies want to productize creative works so that they make money. They do not consider these works to be common to all, but their own property, with which they can do as they please. (This includes removing an unprofitable work from public use, such as books and music which do not sell. Since this is their property, they can stop selling it and bury it so that no one can have access to it. This was more difficult to do in the age of physical media, but it is now commonplace in the age of digital content.)
Culture is now sold to be consumed in one of two models, either the cable television model (where you pay for it even if you're not using it), or the fast food model (where you pay for something every time you consume it). There is no idea of non-proprietary culture. Everything is owned by a company and sold to be consumed.
(Example: The biggest threat to music sales is used CDs. They're almost indestructable, and used items are dirt cheap. Furthermore, with remastering of old works, the music industry created a huge glut of used CDs, further eroding their sales. The music industry has created a bogey-man in Internet file sharing, which they claim was ruining their business, and pushed for "legal downloads" that they control. Throw in the iPod marketing phenomenon which used slick culture to encourage people to download music rather than buy it on a physical medium, and you've got a culture that is moving away from physical media which can be archived in libraries, found in secondhand stores, privately bought and sold, etc. Instead, we have a download culture where culture is transient. Songs can disappear at any time, and people are licensed to listen to songs, and the license can be revoked at any time. Much more convenient.)
The KJV is available to everyone with no restrictions. If you want the most compelling reason to use the KJV, I think this is it. By using it, you're voting with your dollars against the modern proprietary nature of culture and information.