* its software is free as in beer (this is what made me try out linux)
For almost all practical purposes so is Windows and you can get all the good Linux software on Windows and Mac too.
NO, it is not. Mac OS is not either. Free as in beer means free as in beer - no cost. You cannot LEGALLY get Windows for free. Which leads to the OTHER free, which is free as in freedom - which clearly the other two are not either. You can get all the good Linux software on Windows and Mac? Hold that thought.
* its software is free as in software (this is what made me stay on linux for so long)
Like it or not, users in the vast majority don't care about that and it won't draw them to Linux. As far as the software is concerned that same free software like Blender, Gimp and LibreOffice are available on Windows and Mac too. No exclusivity to Linux.
Again... hold that thought.
* it has working package management. updating software is no nightmare. Windows has to force its customers to update it, because its a nightmare.
yep! But remember Windows has Chocolatey and Mac has Homebrew, this covers many of the free software options and for proprietary software you most often need to go through their updaters whether you're on Windows, Mac or Linux anyway.
It's great that it does what you need but you have to remember that above anything else a computer is a tool to run the programs a user needs and while Windows and Mac run pretty much anything Linux does the same cannot be said the other way around and most standard applications in industry support Windows & Mac but not Linux. It might be more secure and/or more stable and free of charge and open source but none of those things matter if it doesn't run the applications I need.
So it's a chicken and egg problem, if you want people to use it they need their applications to support it and to do that you need users. So what you need to offer is some disruptive innovation, some great feature that draws people to Linux, something so good that they would be willing to temporarily forgo the lack of applications and work through the kludge of dual-booting or VMs until their programs supported Linux as a first class citizen. But for the entire life of the hundreds of Linux desktop distributions none has ever offered the user such a feature(s).
Now you can pretend this isn't true, mod it down and fantasize about how desktop Linux is simple held back by a big conspiracy perpetrated by Microsoft and Apple but the fact is it has succeeded incredibly in pretty much all other markets including those in which Microsoft and Apple participate - and it dominates! Server? Dominates! Embedded? Dominates! Mobile? Dominates! Desktop? Utter failure!
So you say Linux dominates in server, embedded, and mobile. So remember what the question was - why do you use linux? The three word answer could very well be "Server, Embedded, Mobile".
And if you don't like the linux desktop because you like or use something that isn't supported on it, that is ok too. I don't think that is an utter failure, however. That is more up to the applications than the OS. There is nothing the OS is doing to prevent them from creating a version for linux. Which brings me all the way back to where I said to hold that thought. Do you know WHY apps that are on linux are also on Windows and Mac? Because of the openness, the other freedom mentioned above. It's not ABOUT exclusivity. It's not about cornering market share, or keeping secrets, or patents, or obscurity, or profits, or lock-out, or lock-in, or backroom deals, or crushing the competition.
I use it, and have used it exclusively outside of my job, since 1998. No dual boot, no VM. It does everything I want. I can't say it hasn't been frustrating at times, but I have never ONCE considered going to windows or mac. It meshes well with my brain and how I think. The desktop is great, and I find it much better than any Windows version (even 7)! But I think that the only thing that it is really missing is in the corporate space. That is where I use windows. There's no conspiracy theory there, they became the standard for that by any means necessary. (see those things above that linux is not about) And that's OK. It's fine to me that Windows has the corporate market, it doesn't really bother me. To me, that's work. It's using a few programs, to accomplish a few goals. Obviously linux is capable in that arena, but to be honest, too many people/companies have invested in the Microsoft way to choose another. I understand, it's a big leap to even consider moving away from Windows. That is really the only argument that I see when talking about why linux hasn't conquered the desktop. People use Windows at work, they use it at home. (not to mention when you buy a computer, it has windows on it) But I digress.
My three words as to why I use Linux: Because It's Linux.