The system package manager and the language package/dependency managers do a very different task.

The distro package manager delivers applications (like Firefox) and a coherent set of libraries needed to run those applications.

Most distro package managers (except Nix and its kin) don't allow you to install multiple versions of a library, have libs with different compile time options enabled (or they need separate packages for that). Once you need a different version of some library than, say, Firefox does, you're out of luck.

A language package manager by contrast delivers your dependency graph, pinned to certain versions you control, to build your application. It can install many different versions of a lib, possibly even link them in the same application.

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skydhash 5 days ago | parent [-]

But I don’t really want your version of the application, I want the one that is aligned to my system. If some feature is really critical to the application, you can detect them at runtime and bailout (in C at least). Most developers are too aggressive on version pinning.

> Most distro package managers (except Nix and its kin) don't allow you to install multiple versions of a library

They do, but most distro only supports one or two versions in the official repos.

	▲	rcxdude 5 days ago \| parent [-]
		Maybe you want that, but I generally want the version of the application that the devs have tested the most. I've dealt with many issues due to slight differences between dependency versions, and I'd rather not provoke them. (That said, I do like debian for boring infrastructure, because they can keep things patched without changing things, but for complex desktop apps, nah, give me the upstream versions please. And for things I'm developing myself the distro is but a vehicle for a static binary or self-contained folder)