Sounds interesting, I'm familiar with Nix, but not Guix. The core tenets of Nix really resonate with me, and you're 100% right in your parent post: this does not solve dependency management. It is a hack which trades long term reliability for short term stability and ease of installation.

It is not The Answer, it's just an answer until we (and I'm glad to see there are people like yourself on the case) can do better.