Perhaps I'm wrong but I think I not only agree with the nix dev in that thread, but I also think it seems kind of the opposite case to what the gp was describing in their second point.

From the gp's post:

> Their technical foundation is so far ahead of mainstream systems [...] they've forgotten how to live a day in the shoes of a mere mortal. Try pointing out flaws in the user experience [...] If you want to spread the amazing potential of Nix to everyone, then you need to compromise with a flawed, imperfect world. You need to meet users [...]

The definition of "user" can be vague, but if you're talking about "mainstream" and "mere mortals", I don't think setting up Haskell dev environments are the primary use-case. As was commented in that thread:

> It's what most distros do. (Only gentoo diverges from the big ones [...]

Favouring simplicity and focusing on supporting only production environments seems exactly the kind of user-focused pragmatism the gp would rather.

I'm not on Nix (yet), I use Debian; I use Apt to maintain my kernel, browser, video player. I don't use it to install dev dependencies.