[eiro]

Perl lost popularity when people were using windows, learnt programming with java, were scared by unix idioms, implicity, regexps, contexts and concepts like anonymous blocks you can map/filter with. nowadays everyone finally think those features are cool (maybe even C23 will have lambdas) so perl wouldn't have lost popularity. I'm still waiting for 1 other interpreted language to have something as convenient as the CPAN ecosystem.

However I see one similarity between C++ and Perl: for decades, they evolved a lot from there ecosystems and nowadays, both C++ and Perl could be difficult to learn just because you can't figure out what module to use to get the job done. Also Perl suffers the lisp curse http://winestockwebdesign.com/Essays/Lisp_Curse.html (I don't know about C++).