To be fair, all of these language specific package managers make distribution packaging easier as well. It's super easy to make a package for anything distributed as a CPAN package, Ruby Gen, NPM package, distutils/setuptools package, etc.

The real problem comes when developers start using these package managers with reckless abandon and letting their dependency tree grow out of control. I don't mind packaging an extra library or two, but a dozen or more is pushing my patience.