For me, the packaging mechanism itself is a less important step than the idea of distributions: can I set up a collection of packages that is known to be mutual

For me, the packaging mechanism itself is a less important step than the idea of distributions: can I set up a collection of packages that is known to be mutually compatible? Or is the approach "one repository to rule them all"? This is where I always (when I was poking at it, a while back) ran into trouble with Cabal and Stack. It was always possible (likely, in fact) that I would select some set of libraries that managed to be mutually incompatible, so I had to go version-chasing to get something that worked. This is something that Linux distros had to solve right from the start, so it's built into the concept, but I only very rarely see it done at all, let alone done well, in language package managers.