[silentbicycle]

For one thing, there's conflict between using an OS-level packaging system (such as Debian or Ubuntu's package repositories, BSD ports, etc.) and a language-level packaging system, and mixing the two often doesn't work so well.

Also, as a language, Perl occupied a somewhat unique niche for a while. It certainly had a head start on other scripting languages, and I think most other languages at the time had issues with portability or multiple implementations that could prevent such a project from achieving escape velocity.

While we're just listing things, Lua has LuaRocks (http://luarocks.org), Chicken Scheme has Eggs Unlimited (http://chicken.wiki.br/chicken-projects/egg-index-4.html), Haskell has hackage (http://hackage.haskell.org/packages/archive/pkg-list.html), etc.