For me, the choice is a trade off between the journey and the destination.
Destination is the final objective of your project, business value or whatever.
The journey is tinkering with "stuff".
Depending on the project there's value and enjoyment in both.
Doesn't fit in this case, I'd say Nix is still cutting edge.
It may also be simple, but it's not easy (in the Rich Hickey sense).
However, learning Nix / NixOS is quite difficult - it requires a specific set of skills (functional programming, shell, Nix building blocks which you can learn from existing Nix code), the documentation is lacking, error messages are cryptic, debugging support is bad.
The truth is tautologically unhelpful: choose good technologies.
Most people have trouble separating snake oil and fads from good things, so old/boring is a safe heuristic.
Nix is not boring, but it is honest. It's hard because it doesn't take half measures. It's not an easy learning curve gaslighting to you to a dead end.
But taste in choosing good technologies is hard to teach, especially when people's minds are warped by a shitty baseline.
This is a really good way of describing a certain type of technology. I'm stealing this line.
I was really pro Nix at the time I took on a rails project and it caused many problems for my team due to Nix just not having good support for my use case. If I could go back in time I would definitely choose something else.
I absolutely agree language-specific package managers need better support. Nix RFC 109 is a simple-stupid way to get some "important from derivation" in Nixpkgs, so we can collectively dogfood them "lang2nix" tools and finally make them good.
It is really sad to me that many users understandly think "hmm, C is crazy, surely this Nix should be even better with more uniform language ecosystems packages!", only to die on the hell of the lang2nixs all being just not quite good enough. This is huge stumbling block for developement shops that try to use Nix that I want to see removed!
The rails support was more of just to handle packaging existing software as opposed to being good for a development environment.
I've not used Nix so I legitimately don't know (but I am quite interested in it)
Typically, technologies I see described as boring have poor features for managing complexity.
Usually with poor reasonong justify meeting some silly definition of "simple“ and "boring" that ultimately makes your life harder.