Being out of print doesn't make sense in today's digital world. Because everything is available online, which is similar to having an infinite number of copies of everything. It doesn't cost anything to reproduce digital content electronically.
If a porn movie is 'out of print' then it's either lost forever or pretty soon it will be. Because DVDs and other digital media deteriorate within a few years after production.
The only way to prevent digital content from disappearing forever is for many people to have many copies it. Because at least some people will care enough about the content to keep making back-up copies of it. People need to be real fans to keep doing something like this for years and years without end.
But unfortunately copyright laws make it too expensive for fans to acquire extensive collections of old porn and preserve it for future generations. There is no such thing as public domain or freeware in porn. Porn companies would rather let their old content rot into nothingness, than give it for free to porn fans, who care enough to preserve it.
The problem with compilation films isn't just that they often don't have any record of where the scenes came from. They also have a problem with creative cutting and pasting that mangles original scenes and makes them different from what they were before. Compilation films often show only a part of a scene and not the whole thing.
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