Let me just reiterate the coolness of Cantrell's CPAN Dependencies --this one illustrates the problem especially well. While the percentage isn't entirely fair, there is much truth in it.

Part of what makes Perl cool and successful is its portability, which it achieves by requiring little of the host system. Another part is its ability to work with whatever external packages are available. Thanks to CPAN it's not quite the same situation for Perl modules, but I think these criteria still apply.