[derefr]

Package management, to me, is mostly about the ability to have a list of sources (feeds of versioned signed package manifests); for updating to generate a merged manifest; and to install, uninstall, auto-upgrade-with-dependencies, and pin/unpin versions of the packages from that merged manifest.

OSX actually has softwareupdate(8), which does work like this—and which at least the OSX system updates (managed now through the MAS app) execute in terms of—which could theoretically be fed custom catalogs (sources) in addition to Apple's, to get most of this part of the benefit. Never heard of anyone doing that, though.