We're almost 60 years past the start of the Unix epoch*. A lot has changed. (Ken Thompson is 82, Brian Kernighan is 83, Dennis Ritchie died fourteen years ago, Kirk McKusick and Eric Allman have been married twelve years but have been a couple longer than that). Proprietary Unix is still alive and Oracle bought out Sun Microsystems fifteen years ago and Larry Ellison is the second richest man in the world, but some form of GNU/Linux dominates servers and keeping the cloud afloat. Amazon Web Services, Google Cloud Platform, Azure, OpenStack, Apache CloudStack, and Rackspace are all based on GNU/Linux. Its popularity for desktop users is also rapidly increasing, with some estimates of around 3% which can be partially attributed to Windows 10 reaching its end-of-life, along with the difficulties around the compatibility of some computers which bundled with it upgrading to Windows 11, and growing frustrations with Microsoft's modus operandi including its automatically included telemetry.
But Linux is (Micro)softening. Nine years ago, Micro$oft joined the Linux Foundation and unveiled Windows Subsystem for Linux. No longer do Windows users need to use virtual machines or dual boot and from Windows 11 onwards, the WSL is already installed by default. One can choose from a number of distros to use with it from some much loved longrunning heavyweights like Debian, openSUSE, and Fedora, to the increasingly popular Arch Linux. While it may it may be helpful to some out there, WSL is not the same as an install of GNU/Linux in many respects, not all of which I understand, but my understanding is that this is less desirable in some ways than the use of either a traditional dualboot or virtual machine. Seven years ago, Microsoft bought out GitHub for $7.5B (more than they paid for Skype, for perspective). But adding insult to injury is the decision to scrape it and folding it into CoreAI (I'm going to write musings on the use of FOSS by corporate entities in future). There's even now a Microsoft Linux certification one can get. Yep, you read that correctly. Some things really have changed a lot in computer culture even just since the early 2000s when I started caring more about this stuff. Some people out there, in both high and low places, have embraced "If you can't beat 'em, join 'em" with seemingly little to no reluctance. (What does it say about you that's your personal motto?)
Maybe Linux itself was never intended primarily to be countercultural, but many of us who adopted this kernel did so out of some form of idealism that had crossover potential outside the ranks of the types you'd normally associate with caring about something as nerdy as software freedom as a political value, even if it's not too far outside of that. (Stay tuned for another spiel on this). For what it's worth however, I do still use Linux more than any other kernel on my machines, and as of the time I am writing this, and there is still a lot I do still very much love about Linux (which I will also write about in future), though to a large extent moreso about copyleft generally than Linux specifically.
Yet I am also increasingly drawn to NetBSD, one of the offshoots of the Berkeley Software Distribution (of Unix). If memory serves, its popularity in this category sits in roughly fourth place, with a chunk less of a userbase than OpenBSD, (which initially began as an off shoot from NetBSD), and a goodly amount more people using it than DragonFly BSD. Here's a short, humorous, reductive, sometimes entirely unserious look at why not to use some other options. FreeBSD might as well be Linux, for better and for worse. I don't know if I'm quite paranoid enough for OpenBSD (<G& gt;) but even moreso, I'm not the super keen on the benevolent dictator for life model, whether that's Theo or Linus. DragonFly BSD, the only jokes I can make are based on confusing the project leader Matthew Dillon with the more famous actor Matt Dillon. GhostBSD only works on amd64 processors. macOS/iOS/iPadOS/etc. are really not what anyone except pedantic software genealogists ever mean when discussing BSD.
Three words: time. machine. appeal. There's something fun (and educational) about being able to continue to use and do things the same way or similarly to how they are found in decades-old textbooks and manuals.
see my pinned why i'm a toasterhead for the more positively-framed answer to the question
* The Unix epoch, which is the basis of how Unix and Unix-like operating systems (and some other software) measure time is based on seconds since 1 January 1970. In a few days, 2026 will be upon us and the apocalypse will be only a little over a decade away.