Copyright is a double-edged sword. On the first edge, it's amazing that after a certain amount of time, and under certain circumstances, every book, every story, every beautiful creature of the imagination that was ever created will enter the public domain, from which point they will be forever free for all to enjoy at no cost.
Dancing on the other edge of the blade, when it comes to classic SF stories from now defunct genre magazines, even when the stories are out of copyright they are often hard to find, expensive to obtain (in terms of time or money), and rarely available in a modern digital reading experience (phone, tablet, ereader, etc.)
With one exception.