With CPAN (and local-lib and/or perlbrew) I can have per-user libraries, per-application libraries, and it doesn't interfere at all with the dependencies of the

With CPAN (and local-lib and/or perlbrew) I can have per-user libraries, per-application libraries, and it doesn't interfere at all with the dependencies of the system. If a library that both my application and the system use, and they fix a bug that includes an incompatibility, I can upgrade my applications without fiddling with the system, I don't need to take care to break APT in the process (fun times). I'm not even talking about possibilities like copying someone else's local-lib to my own environment to help them debugging, while still having my own setup stay untouched. So, I guess I disagree. These tools provide a lot more than the usual package management. To me it seems backwards to try to manage libraries globally when their use-cases are often already localized.