The chart I'm seeing says Perl is the top 20 or so most popular language on GitHub with about 146 million lines changed "recently". I'm not sure that's the biggest disaster considering Perl had its own distribution and deployment network years before GithHub existed. Sure, it'd be nice to see it closer to where Python or PHP are. Yet people make a handsome living with Clojure, R, Erlang, COBOL, and others that are well below Perl on that chart.
As for the job seeker chart, although the absolute share of job postings is low for Perl (although it seems to be recovering from a trough there at the end) the number of jobs per seeker is quite high. That's a good thing if you're a skilled job seeker. It's also probably why some of the listings don't mention it. They'd rather recruit skills they can fill more easily. Get more people to look at that 4 jobs per seeker chart and the market will even out a bit.
C++ is a great pun of a language name. It's a nightmare for search engine users. C isn't much better. Notice the tendency to use "golang", "Rlang", etc. with some of these names. Unsearchable names are a real problem.