I've been complaining about this for a while regarding source code. The notable example I can remember pointing this out was Star Control 2 (Ur Quan Masters is the name of the Open Source release.) Due to the fact that they weren't required to SUPPLY a copy of their copyrighted work/code/etc in order to obtain copyright, the original source code for the DOS version of the game was lost years ago. Toys for Bob, the guys who had programmed it (But not distributed it, which is why it's not called the SC2 Open Source release) decided after many years of fan interest to allow a full open source release of the game, datafiles and all. However they'd lost the master source code for the game years before, which resulted in the release instead of the 3do version of the source code, which thankfully HAD survived all these years.
My point with this being: In the 50-100 years or so when CP/M, MS-DOS, PC-DOS, Microsoft Windows 1.0, etc should be coming out of copyright, allowing people three to five generations from now to benefit from being able to explore the code behind the massively successful and historic works, those works will not exist, because in the greatest travesty of this generation (and there are many, both great and small), all of that information, code, documents, film, etc will be lost, because nobody other than the 'owners' was allowed to look at, back up, save, translate, and otherwise secure those culturally significant treasures for future generations. (And yes some people might not consider these items 'treasures' but they are important to both outlook and understanding of what went on during the latter half of the 20th century on through to today.