I don’t mean to sound crass here, but the best answer I can give you is, “because I want to”. I wouldn’t go as far as to say that I will pursue Linux professionally as a job. But who knows? I wouldn’t out-rule that.
It’s something that I am passionate about and enjoy using. Therefore, I will naturally want to grow my knowledge in.
Oh, I agree with you. I have brushed off dozens upon dozens of distros, because they just do not offer anything over Arch linux that I have always been using. Until NixOS entered my radar, that is. NixOS has many very unique strengths that you just can not get anywhere else. Due to that, it was the first to make me question whether I should make a switch to it or not.
However, I disagree that a “ton of knowledge” transfers. Putting aside the programs one uses, the way you set up, configure and maintain your system will wildly vary from a standard distribution. Which will not help you at all in case you want put all what you have learnt into another machine that requires said ‘normal’ distribution. But again, I understand that this is the whole point of its design in the first place.
When you learn NixOS, you learn NixOS rather than Linux.
That is exactly what I am talking about. You seem to have understood me the most. NixOS could be the unequivocally best distro ever. However, that does not change the fact that a big portion of your knowledge acquisition and experience gained from your time on NixOS, will be for NixOS alone.
I am obviously not putting the two on the same line, but mac shares a lot of terminal syntax and programs with Linux. They still remain vastly different. So, this is exactly what concerns me with the growth that I seek in the Linux ecosystem.
These are the kinds of comments that made me start researching NixOS in the first place. Damn it :D