I was lead on a Nix adoption effort for a few years that was kind of like that: it solved real problems, unlocked far faster, smaller, and cheaper builds than would have been possible any other way, and let us ship delta updates over crappy wifi connections to Linux computers on robots. Flakes were a perfect fit for our model, and we were just in time for stuff like up to date versions of cuda and tensorflow to be delivered via nixpkgs.

In my mind, Nix was unstoppable, and I particularly loved how empowered I imagined developers would feel. No mystery-meat CI scripts pushing packages to distant infrastructure that no one understands or even has the permissions to interact with, just the entire build system in one repo, trivially cloneable and hackable... add patches or build steps to anything and it's the same build as always, build it locally or send it to Hydra, it doesn't matter.

A devs "got" it and did leverage those things, used PRs to do safe evaluation of bumps to core dependencies, but I think on the whole it was regarded as cool but not tractable, and a few years after leaving, it sounds like plans are being laid to replace it all with something containers or whatever.

Very frustrating, particularly in a world where it should be trivial to identify the 5-10 typical tasks that people want to do with the nix code, and set up Claude skills to handle those. Given how easy and self-contained the build-test loop is, it feels like an almost perfect fit for agent-led development.