Nix&#x2F;Guix have been brought up a bunch of times in follow-ups. I was aware of Nix (though not Guix) before writing the piece, and I do need to check it out. But...<p>The primary requirement for a PDM is that <i>developers will actually use it</i>. If the interaction is much more complicated than the command diagrams I laid out towards the end of the general section, it&#x27;s really just not gonna happen. Maybe someone could build a guix frontend that focuses in on just those things. I don&#x27;t know. New territory for me.<p>My guess, though, is that SPMs and PDMs are really only superficially similar.