This blog post deals only with the social and "human" aspects of various technologies. It is not about the technical merits of any programming language or other such tech. If you intend to write a scathing Reddit comment along the lines of "this guy is an idiot, Perl is a great language for X because you can do Y, Z and W", please don't. That is not the point of this post. Perl was chosen as the canonical example mostly due to its prevalence, the same points apply for things like CORBA, TCL, needing to write XML files by hand, ridiculously long compilation times and so on.
What is the issue at hand?
The 90s and early 2000s a lot of code was written. As was fashionable at the time, a lot of it was done using Perl. As open source projects are chronically underfunded, a lot of that code is still running. In fact a lot of the core infrastructure of Debian, the BSDs and other such foundational projects is written in Perl. When told about this, many people give the "project manager" reply and say that since the code exists, works and is doing what it should, everything is fine. But it's really not, and to find out why, let's look at the following graph.
As we can see the pool of people willing to work on Perl projects is shrinking fast. This is a major problem for open source, since a healthy project requires a steady influx of new contributors, developers and volunteers. As a first order approximation, nobody under the age of 35 knows how to code in Perl, let alone would be willing to sacrifice their free time doing it.
One could go into long debates and discussions about why this is, how millennials are killing open source and how everyone should just "man up" and start writing sigils in their variable names. It would be pointless, though. The reasons people don't want to do Perl are irrelevant, the only thing that matters is that the use of Perl is actively driving away potential project contributors. That is the zeitgeist. The only thing you can do is to adapt to it. That means migrating your project from Perl to something else.
But isn't that risky and a lot of work?
Yes. A lot of Perl code is foundational. In many cases the people who wrote it have left and no-one has touched it in years. Changing it is risky. No matter how careful you are, there will be bugs. Nasty bugs. Hard to trace bugs. Bugs that work together with other bugs to cancel each other out. It will be a lot of hard work, but that is the price you have to pay to keep your project vibrant.
An alternative is to do nothing. If your project never needs to change, then this might be a reasonable course of action. However if something happens and major changes are needed (and one thing we have learned this year is that unexpected things actually do happen) then you might end up as the FOSS equivalent of the New Jersey mayor trying to find people to code COBOL for free.