I've been using -nix for almost 20 years. I've used everything from ksh on SunOS 2.6 (Solaris?? what's that) to oh-my-zsh (for 3 years, before happily graduating to oh-my-fish). I grew up on Slackware 6 waiting hours and hours for a 2.2 kernel build to finish. In high school, FreeBSD 4.3 kernel mods took up more time than booze and women. My 3 year puppy love for oh-my-zsh dimmed as I transitioned to a more sane, less emotional woman - oh-my-fish.
I hate to admit it, but Microsoft just got it right with Powershell. Standardizing the convention with an intuitive Verb-Noun, the out of the box documentation with -examples, -full, etc goes into so much detail that if everyone used it, there wouldn't be any dumb "How does I move directory??" questions on Stackoverflow (well, there'd be less at least).
Don't know a command? Show-Commands and type in 'network' to see what's available. Don't see it there? Go get a Powershell script (often offered by vendors like VMware and Citrix, making devop lives easier). I remember spending _weeks_ trying to get my dual-boot machine (FBSD / Win2k) Cygwin/msys setup to work well on my P3 600 at 12 or 13. Now I can just Feature install Bash and get a native binary. Let me say that again -- now, I can Feature install Bash on Windows jeeebus. QT is LGPL. CLR is open source. Visual Studio Community (basically Professional) is free (unless you need historical debugging then Ultimate's going to cost a lot). Satya + Meijers + Hanselman et al have made favor Microsoft so hard, despite being an active donor of the FSF.
That GNUutils-with-autocomplete is real trivial to write, but since it's already in fish, I see no need to right it. :smug: [In all seriousness, I agree with you re: standards. Plan 9's interface standards semi-addressed that. But le sigh such is life.]