I think the fastest way to convince yourself that Perl is obsolete is to try to hire for good Perl programmers. It's a fine language if you treat it well, but it's going the way of COBOL.
It's not _that_ hard to hire good Perl programmers. Maybe it depends on they scale you need to hire for, but I've been involved in the hiring process for a couple of Perl positions and I've seen lots of really strong candidates.
I'm not really sure why you can't hire a Ruby or Python programmer, if they are open minded about it, and train them. There's not that much actually different, compared to some other languages. In fact, I think the only major things you would need to teach them that they couldn't easily find from the docs would be about how context works, and references (references to a lesser degree, just make sure they get how they are used in complex data structures).
> I'm not really sure why you can't hire a Ruby or Python programmer
Yeah, sure, hire a Ruby/Python programmer ... and try to trick them about the language they're going to be using by being vague about it in the job posting and initial conversations until they got really interested?
Been there, done that. It was a stopgap measure that sort of worked and it wasn't that much fun.
No, just advertise appropriately. Some people don't apply because they don't want to use the language, others don't apply because they expect you to require skill in that specific language. Something along the lines of "Knowledge of Perl or equivalent dynamic language strongly suggested."
