Perl didn't just fall out of fashion. It failed as a language because it wasn't able to keep up with what other languages could do in practice. The people behind Perl recognized that, but weren't able to agree on a solution. So usage of the language collapsed.

A big part of the problem wasn't that you couldn't write good code with Perl, but that there were too many ways to write bad code with it. That made it anathema for any sort of corporate development, which is the main driver of programming language progress.