I also guessed that the lack of dedicated maintainers is due to a lack of volunteers, but that's something that stops me from using either guix or Nix at least from handling the critical part of my OS (kernel and base system).
For development environments and other stuff, both are great tools, but I guess the real power comes when you manage the whole system through any of these managers.
NixOS/nixpkgs [1] was at some point last year one of the most active projects in GitHub. I can't find the ranking right now, but it should suffice to say it has 2083 contributors and 178334 commits right now. For a relatively young project, that is a lot.
There are tons of dedicated maintainers. You can see that in the maintainers attribute of most packages. So I don't get your point regarding the lack of dedicated maintainers.
I maintain several packages there, and a bot sends me an automated message every time upstream updates the source, and auto-generates a new package definition for me. Things are really streamlined and bleeding edge. The unstable channel is often more up-to-date than Arch Linux even, due to the high number of Nix developers.
Thanks for the insight in the maintainer story of Nix. I guess it is kinda the same for guix and this more or less invalidates my concerns. So maybe the next time, I reinstall my OS, it's gonna be one of those :)
For development environments and other stuff, both are great tools, but I guess the real power comes when you manage the whole system through any of these managers.