Yes they do become public domain eventually. Basically, for books, plays, musical works and art here in the UK, it's 70 years from the end of the year in which the author dies. For sound recordings, 50 years from the end of the year in which it is released. As with any legislation, there are all sorts of limitations and caveats to that, but those are the starting points.The pop artists don't like it, because their early work starts to run out of copyright when they get to their late 60's and early 70's, when their popularity is well on the wane and they may well need the income.
