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.
Don't sell perl 6 short. I am using perl 6 for significant projects now (after a career of perl 5) - and it's fundamentally different. I describe it as perl to the power of perl.
For me, expressiveness is fundamental. And perl 6 gives me that.
Perl 6 is simply suffering from python being everywhere. And perl 5 was always easy to lampoon as "line noise". It's a stupid quip, but it leaves a mark on new programmers. You don't even need to read the course and you can already have an opinion. Stupid kills? And then perl 6 doubled down on that anyway. Then I doubled down on that ALSO and I get to use (carefully chosen) unicode symbols in my line noise :-) So there.