People are interested in using it and people are interested in developing it, so it continues to be used and developed.
I got my start with Perl; I wrote a book about it, I spoke at every conference, I did training, I maintained the Emacs mode. I started working at Google and, forced to use static languages, found them to be just as productive as Perl. And, they eliminated a lot of problems with Perl -- libraries were resolved at compile-time, and I just ended up with a binary that could be run anywhere (no @INC madness); types were checked at compile-time, so silly errors that required extensive unit testing in Perl could just be automatically underlined by my editor and fixed before I even saved the file.
Something else that bothered me was how much mindshare the dynamic languages were competing for among themselves. I would prefer to write a Perl program over a Java program any day... but Perl did not seem to be fighting with the Javas and C++s of the world, instead it was always trying to take on Python and Ruby. And Python and Ruby were like that too -- every Ruby programmer was out to kill Perl because they didn't like Matt's Script Archive. (Nobody wrote 1990s Perl in the 2000s, so it was kind of a strawman.) You ended up with a bunch of like-minded people fighting for the small attention share of "we don't really care about runtime performance", and all the factions were just too small to take on the larger issue of entrenched static languages. Java and C++ never felt like they had to take features or ideas for Perl, Python, or Ruby. So it all seemed kind of pointless.
With all that in mind, I do think Perl failed to "win". It is a neat programming language, but probably too complicated for beginners and not productive enough for people that have gotten comfy with C++/Java/Go, which are pretty darn productive these days. Meanwhile, Python found its niche pretty much everywhere -- you can program microcontrollers with it, you can write a video sharing website with it, you can do data science with it -- and it's a great introduction to programming for beginners. And, Javascript kind of came out of nowhere to conclusively "win" the dynamic language war (because a dynamic language needs a runtime, and guess what runtime exists on pretty much every computer and phone around these days?)
TL;DR: I kind of agree that the programming language wars have been fought and lost by Perl. That doesn't stop people from wanting to make it better, or to continue to use what they know. You can make lots of great things with it, so people continue to use and improve it.