By the time Perl 6 was around, Perl's lunch was already eaten by Python. Only a few table scraps left. Perl 6 would have had to be a better Perl 5 and a better Python 2 to win.
Python came with better batteries and better syntax. It allowed producing code you could read and understand a week later. Perl I found was a write-only language for me. I went back looking at my old Perl code and I couldn't decipher it without some effort.
And Python became popular not just because it was a better Perl, but it attracted folks who used Java and C++. CPU speeds were getting fast enough that you could actually do file and network IO at acceptable speeds without all the `public static void main(String[] args)` and `System.out.println(...)` boilerplate, but still had all the object oriented bits like inheritance and composition with which you could go crazy with if you wanted.
Perl exploded because it was the easiest, richest ecosystem available to plug into CGI and the web.
PHP & Ruby & Python then collectively covered the same waterfront whether you wanted “easy” or “fun” or “simple”.
And I would propose that PHP attracting the developer cohort who wanted “easy” and Ruby/Rails attracting the developer cohort who wanted “fun” were each individually more damaging to the Perl ecosystem than Python.