But why does every language need its own system? They aren't that different from package managers view that a generic solution wouldn't work.

Okay, but you'd have to come up with one, write it in cross-platform C and then have bindings for each of the target languages. And then you'd have lots of people complaining about missing features (or too many features), and quite a lot of them would still use another toolset. Never mind getting everyone to agree on the same repository...

Considering the balkanization of even the Linux binary package market, it's not very likely to happen, both for political and technical reasons.

It wouldn't need bindings for every language. Packages usually are just a bunch of files with dependencies and some other metadata. Nothing in that is language-dependent.

And not everyone needs to use the same repository either. Again, apt does handle multiple repositories just fine.

I meant the same repository software/format. Try to convert CPAN...

And you'd need language bindings for selecting the properly installed package (language modules need to be multi-version capable). Things like "gem 'activerecord', '= 1.4.0'" in RubyGems, or Maven's dependency resolution.

But again, the technical difficulties pale before the political ones. You'd have a much larger chance of success concentration on one platform (e.g. Debian), creating some automatic gem/egg/CPAN converter and then wrapping the language-native tools to use that. Whether that's actually worth the effort…