@cwebber yes, but. I was using nixos in 2015-16 or so, at which time docker was still young enough (iirc) that it required unionfs and other weird hacks. We could have gone Full Declarative back then, but the Dockerfile - it's just shell commands one after the other - is a much easier sell to sysadmins than "btw you have to learn scheme" or even "btw you have to learn this weird ml-syntax-but-no-types lazy-evaluated language you've never seen before"

I don't know the state of the art on Guix, but even in 2023 I would still be cautious about recommending Nix for packaging, say, a large Rails + React monolith - especially a closed-source/internal one

@cwebber I think the technical side is only part of it; it's no coincidence the two big containerized solutions on Linux are from Canonical and Red Hat respectively. Both were always going to want their own equivalent of an app store in the sense familiar from proprietary OSes, especially if the other had such a thing.

And some of the downsides of "bundle all the libs with your app" approaches aren't even seen as valid downsides by many engineers; many devs, especially proprietary devs, *want* to basically just ship their exact dev environment with no change, because they Know Better.

A depressingly large number of software devs (in my experience especially ones with engineering degrees...) get very frustrated when their software doesn't compile or otherwise work right on others' systems and refuse to consider that this could be showing fragility on the part of their software. Hence, as implied by @technomancy 's quip here, much of the popularity of Docker—"if other environments are so broken they can't run my correct and perfect code, that's their fault" and so the question of portability is solved by petulantly just porting over the entire environment!