The brand-new RHEL 6 includes a modernish version of Perl 5, only three stable releases obsolete. (Perl 5.10.1 is almost 15 months old, and it's also the oldest version of Perl 5 I consider using on any current project.) That's the good news.
The bad news is that RHEL 6 will stick around for several years, just as RHEL 5 did. RHEL 5 uses Perl 5.8.8 (almost 5 years old and six stable releases obsolete). RHEL 4 is also still around. It uses Perl 5.8.5 (almost six and a half years old and nine stable releases obsolete).
By the time RHEL 6 retires in late 2015 or 2016, the current stable release of Perl 5 will be 5.20.2 or 5.20.3. Assuming two minor stable releases of each major version, RHEL 6's Perl 5 will be fourteen stable releases out of date.
Bluntly, RHEL sells you the belief that you can build on the foundation of the software they provide and not worry about the pesky details of who actually wrote the software and how they develop it. For the hundreds or thousands of dollars enterprise customers pay Red Hat to support obsolete software such as Perl 5, Red Hat employs (to my knowledge) no core Perl 5 developers. That is to say, your support dollars don't actually go to anyone with the knowledge or authority to patch Perl 5 to meet your needs, especially after the core developers have explicitly disclaimed responsibility or desire to support ancient releases.
(I don't mean to pick on Red Hat alone here; the latest Solaris release, Solaris 10, includes Perl 5.8.4, six and a half years old and nine stable releases obsolete.)
How can anyone characterize the reliance on a vendor Perl 5 from an Enterprise Distribution as anything other than irresponsible and risky? At some point, maybe it's worth gently nudging these vendors to rename the creaky old software in their default installs to indicate its obsolescence and lack of support from the actual developers of Perl 5. The word encystation has its charms, though I suppose nacre is easier to spell.
For everyone else, free yourself from the tyranny of obsolescence foisted upon you by the Enterprise World and install a modern release of Perl 5 with App::perlbrew.