Yes, you've identified a bad trend. I am trying to raise awareness to stop it.
>And what if your goal is to distribute software to users that may be running any arbitrary OS? You can't tell them "install Guix, learn how to use it, then use Guix to install my app". You'll lose a lot of users that way.
You can actually use Guix to export the closure of the build and distribute that, if that's your thing. We do this for Guix itself to greatly simplify the installation process for new users, though for your use-case there would be some adjustment needed. The resulting binary distribution would work on any GNU/Linux system. Nix additionally offers OS X support. But yes, not everyone's use-case can be covered by Guix right now, but I strongly feel it's the direction we should be moving in.