Rather than its "decline was", Perl's existence is cultural. All programming languages (or any thought tools) are reflections and projections of the cognitive values of the community who creates and maintains them. In short, the Perl language shares the structure of the typical Perl dev's mind.

A shift to Python or Ruby is fundamentally a shift to a different set of core cognitive patterns. This influences how problems are solved and how sense is made of the world, with the programming languages being tools to facilitate and, more often than not, shepherd thought processes.

The culture shift we have seen with corporations and socialized practices for collaboration, coding conventions, and more coincides with the decline of a language that does in fact have a culture that demands you RTFM. Now, the dominant culture in tech is one that either centralizes solutions to extract and rent seek or that pretends that complexity and nuance does not exist so as to move as quickly as possible, externalizing the consequences until later.

If you've been on this forum for a while, what I am saying should seem familiar, because the foundations have already been laid out in "The Pervert's Guide to Computer Programming", which applies Lacanian psychoanalysis to cognitive patterns present in various languages[1][2]. This explains the so-called decline of Perl—many people still quietly use it in the background. It also explains the conflict between Rust and C culture.

As an aside, I created a tool that can use this analysis to help companies hire devs even if they use unorthodox languages like Zig or Nim. I also briefly explored exposing it as a SaaS to help HR make sense of this (since most HR generalists don't code and so have to go with their gut on interviews, which requires them to repeat what they have already seen). With that stated, I don't believe there is a large enough market for such a tool in this hiring economy. I could be wrong.

[1] [PDF] -- "The Pervert's Guide to Computer Programming" https://s3-us-west-2.amazonaws.com/vulk-blog/ThePervertsGuid...

[2] [YouTube Vulc Coop]-- https://www.youtube.com/watch?v=mZyvIHYn2zk