I suspect that people's opinions on this debate are highly correlated with whether or not they have worked in an environment where they were forced to use an older version of Perl (or other similar package).

This is a simple, yet tremendously profound comment. For many organizations, upgrading language tools is a hairy business -- hence the reason I have to support compilers for the thirty-year-old F77 standard. Today, I have systems in production that run perl 5.005, 5.6.0, and (several variants of) 5.8.x. I'm hopefully eliminating the two older of these versions, real soon now (TM) -- but I expect the 5.8 tree will be around for some time. This is primarily because 5.8 is "current" for the OS versions I am using, and getting approval from the software police requires approval from God, Congress, and Griffin (the mythical creature, not that guy in finance :)).

I am primarily a module user, and all the modules I write are for internal use only -- but I know the pain of trying to code for a perl rev that doesn't support 3-arg open() or function prototypes. Occasionally, that situation forces me to defer code reuse and roll my own because I can't find a compatible version of the .pm I want.

Based on this experience, I can completely understand why module writers don't want to be burdened by trying to get their code working under older Perl revs. I am also extremely grateful to those of you who do.