While I agree in the general case (e.g., software aimed at end users), there's also a good reason why the Archlinux Wiki is so good: because installing an OS does require a manual if you want to be able to do any customization at all (yes, you can just install the defaults, but if that's what you wanted, you probably wouldn't be running Arch). And the same applies to systems software not quite as broad in scope as an OS: there can be multiple different customizations you might need to apply, or you might need various dependencies. atoav didn't mention whether the software the sysadmin was installing had a distro package (it might not have even been on a Linux system, no particular reason to assume it was Linux rather than FreeBSD or AIX or Solaris or...), but I kind of assume it didn't, precisely because there were installation instructions. The sysadmin wouldn't have been "swear[ing] his way through an installation process" if the installation process was "sudo apt install some-piece-of-software", after all.

> It should require one button click, or one drag action.

That is way to simplistic to be one size fits all.