> If you want to count them as package managers, they're by far the worst ones of all the well known languages (with some notable exceptions e.g. guix's and nixos's).

The have the only feature I care about: cross-language dependency management.

Unless you are suggesting to reimplement everything in each language and then make users install ten different XML parser, SSL implementations, etc. just because not-implemented-in-my-favorite-language syndrome.