I will say that the extensive backwards compatibility is a big reason why Perl remains; there’s no pressure to change or get rid of “old” programs when they just keep working year and year.
Sometimes I wonder whether Perl left a huge code base behind, like COBOL did, but I suspect it didn't, mostly due to the fact that Perl is a dynamically typed language used mainly for web development and sysadmin scripting.
Perl unlike Java, which had no serious alternative in its niche, unfortunately has an uncertain future in my opinion. Not that Perl is going to disappear suddenly like coffee script, but as the old timers retire or pass away in the next decades, I can certainly see the language slowly "evaporating".
I personally learnt it at the age of 17 as the homemade switchboard for MSN Messenger bots were coded in it.
I'm 36 now and still not letting go. Something about the syntax pleases my brain. I am currently learning Erlang.
I started on Java, PHP, C++ and during my php years i discovered Perl because we needed it at work for systems. I just love it.
I was going to start using it on the cli, but then ended up learning powershell, and then moved to nushell. I don't see myself learning it now.
The main usage were on back office tooling such as reporting back job queues, status of specific jobs, load balancing and the likes.