>>38001
You're an idiot if you think you can apply the concept of free software to original cyberpunk books.
GNU (we'll set this as the point where the concept of free software started existing, even though hacker culture had always share[d] the software) started being developed around 1983, just one year before Neuromancer got released. As you can expect, GNU was a niche project that only a few college students and specialists got to know about, and if you weren't a hacker yourself, it was something you weren't expected to know about. And needless to say, Gibson was far from being a hacker. In fact, Gibson did his research before writing his stories, but you can't expect someone who didn't even have a computer at home to know about some obscure event that nobody expected to become important in the future. Fuck, the completely made up jargon in his novels further reinforces the point that he just had a general idea of how tech worked, let alone how the tech community worked.
As >>38046 correctly pointed out, Linux appeared in fucking 1991, and it would still take some time to become popular. It's physically impossible for a novel written in 1983 to mention something that wasn't even invented yet.
While it's true software freedom has never been a major point in any cyberpunk novel, explicitly stressing that the characters were using proprietary software was also not something original cyberpunk did, and the real reason behind this is probably that original cyberpunk is a fairly soft sci-fi; it explains what stuff does and sets a basic set of rules or laws where they can build from, but it never goes in depth, and therefore software just "is". Stuff just werks because it was made to work like that, but don't ever question if this is practical or even plausible in real life because you might get disappointed.
Why is it soft sci-fi, anyway? The answer is fairly simple: Gibson was not an engineer, and neither were most authors. The level of technical detail he managed to get in his novels was incredible for a novelist who knew fuck all about computers, but it falls apart when scrutinized because, well, he knew fuck all about computers, which is why free software isn't mentioned in his works.
However, if we go a bit farther in the future, we can find movies like The Matrix Reloaded (not Gibsonian Cyberpunk, but it could be considered cyberpunk as well. YMMV) where there is the famous nmap (free software) scene, being used in something that kind of looks like it could be GNU/Linux (free software) just before using ssh (free software as well). Tron Legacy also had a scene where they used Solaris and several Unix commands, and if I am not mistaken, it was also mentioned that Skynet ran on Linux in one of the movies.
The tl;dr of this is that free software isn't mentioned in cyberpunk because its authors weren't huge nerds like us (except Neal Stephenson who actually did write about Linux in "In the Beginning… Was the Command Line", but it was some years after writing Snow Crash). They didn't know why free software is important, and probably never considered the risks of proprietary software, which kinda clashes with the persistent cyberpunk theme of paranoia, and therefore we can deduce they probably just overlooked it.