As a diehard Emacser, Emacs has been waiting about thirty years for someone to make it a prettier wrapper.
It's possible to be so power-user-friendly that in practice no one wants to make it end-user friendly.
In particular, Nix can be used in a non-invasive add-on manner on ordinary distributions. We have it installed on RHEL servers at work, where it is used exclusively as a build system and for "userspace programs" (not in the kernel sense, but in the sense of programs that are not core to the functioning of the system).
In a world where there are thousands of things for me to learn (many of them with poor documentation), Nix is just one such thing.
The question is, do I care about its purported benefits, and sink my time and effort into it, or should I sink time and effort into learning Unreal Engine, playing Rimworld, or going for a walk?
So far, for me (and most of the world) the last three (and the rest of the thousands of things) win over Nix.