Those are hardly equivalent (aside from the obvious differences in prominence, scale and relative importance between Blekko and Twitter).
Scala shops attracts developers curious about new paradigms (FP / FP hybrid) whereas Perl shops tends to repel forward-looking developers who view it (accurately or not) as an ugly throwback to the year 2000.
Put plainly : Scala sells itself (to a certain crowd) whereas Perl needs to be be sold almost across the board. Scala is viewed as an up-and-comer, Perl as a has-been.
The GP argued why a tech choice is good, you answer by arguing the reality -- of the fud! That was quite funny.
Edit: OK, I was talking about the first part, CPAN. You only made claims about jobs (that there are no good Perl jobs being created, which duckduckgo by itself should have killed.)
The parent was making reference to the common notion that using outlier languages provides access to high quality talent. In certain cases this holds true, in others not. You will attract, on average, higher quality talent by using Clojure rather than Cobol.
EDIT (response to parent edit) : well, no. I never said there are "no good Perl jobs", just that Perl is not in and of itself a draw in the way that Scala / Clojure / Haskell might be. You could probably convince someone that there are cool opportunities in Fortran development, but very few are actively seeking them out.
People are learning Python? Really? That was probably true in 2006-2009. Python is no longer the new hotness. Scala and Clojure may be.
The fact of the matter is Perl has a massive niche(Text processing, Unicode, CPAN, Regular expressions, Fast prototyping, TIMTOWDI, Ability to add new syntax rapidly[Moose, Devel::Declare etc], Automation, Testing culture, Documentation, Unix, Parsing, Getting things done real fast... I can go on.. but I will stop here), If you look at what Larry Wall has been saying over the years about Perl 6 in various talks you will note that he designed Perl to fill a niche which continues to be totally unoccupied till today's date. The only competitors Perl has in its design space are tools like sed and awk with a additional few Unix utilities thrown around. In other words Perl doesn't have any credible competition. What's more? Any language that is designed to replace Perl will largely look like Perl(Read: Ruby, Perl 6). And yes, Php and Ruby do have their niches.
Python doesn't have a niche. All Python has is- "Tab indent your code." And sorry to break the bad news to you. Merely forcing indentation on a bad programmer doesn't magically transform him to a good programmer. Rather it make the situation more worse. It gives him a free pass to sit amidst good programmers.
Leaving all about Python aside, what exactly is that niche? I'm not being ironical or anything, I really want an answer to this question, that's why I started this piece of the discussion. Seeing that things like Metasploit, that I would have expected to be written in Perl, end up being coded in Ruby, makes me unable to see any "special niche".
(About what people are learning: indeed we programmers pursue the new hotness, but of people that just started learning how to code, I bet 80% of them are learning Python, Ruby or Javascript, and since this the language they will first learn, this is more likely to become and remain their "go to scripting language" - bar Javascript...).
When we use APL, everything is one line long and code doesn't ever need indenting.