This is one of those things where everyone who even understands the question is going to have an opinion, and the rest will too. I've worked with Perl professionally since 1995 and still do, which doesn't necessarily mean I know what I'm talking about but FWIW here's my best guess.

I think Perl 6 has not taken off because of three things:

1. Other options.

When Perl 5 really took off in the mid-late 90's, building much of the early Web as well as all sorts of business software (we used it heavily in biotech), there weren't so many other options.

For server-side things it was (or at least seemed) faster, easier, and much much newbie-friendlier to use Perl than the other "obvious" languages, C and Java.

Now there are a lot more languages to choose from, inluding ones that share Perl's original virtues of accessibility and "hackability." While some of these newer languages were gaining ground, Perl 5 was enjoying subtle improvements while seeming more and more dated.

We have large populations of potential Perl hackers who have, for good reasons, chosen to develop their expertise in other languages. They have little interest in learning the "new Perl" because they don't have deep knowledge of nor love for the "old Perl."

That at least some of the hot new languages (Go, Swift) have corporate backing with infinitely deep pockets may also be a factor.

2. Hiring death-spiral.

It's very hard to hire for Perl programming jobs these days. We older Perl hackers often move on (or up) and the young folks look around at where the excitement and the jobs are, and they see them elsewhere.

(Perhaps counterintuitively, there are also a lot of young programmers who prefer Java: maybe not much excitement there, but never any lack of employment.)

The fact that it's hard to assemble, grow or even maintain a Perl team means that it's harder to justify developing systems in Perl from a business perspective. On the one hand you have all the advantages your senior Perl hackers can list for you, and on the other hand you have the cold hard fact that the systems they build will one day be maintained by junior devs who wish they were using something else.

It should be obvious that this is self-reinforcing, and I think there are probably thousands of little Perl shops embedded in big companies where the managers have long been dreaming of a path away from Perl, while the senior Perl hackers reluctantly start to agree with them.

This ends up as Perl 6's problem, not just Perl 5's, because the same people who would usually champion the newest version of the language are busy keeping their Perl 5.x legacy systems alive with shrinking staffs and growing pressure to get off that train.

Also, it will be hard to get your management team to back a big push into Perl 6, because they will only hear "Perl" and remember how painful it was to find Perl people the last time, and the time before that.

3. Approachability.

Perl 6 is really cool and really hackalicious but also not super easy to get started with. Where even back in Perl 4 it felt like it was newbie-friendly, the only thing newbie-friendly on perl6.org is the butterfly logo, of which I am not a fan.

Something like the Go Playground[0] would be nice and might help spread the word. As would a story about what Perl 6 is better at than anything else.

As far as I can tell, cutesy "spokesbugs" aside, Perl 6 is presented as something for the Perl crowd. And as noted above, much of the Perl crowd is too busy for it.

A lot of languages get popular because they show you how easy and fun it is to do thing X in them, and you've always hated doing X in whatever other language. I'm not sure what that X would be for Perl 6, but I have a feeling it's something about the writing itself, which might be a hard sell, but I don't really see it being sold outside the Perl community.

...

Anyway, all that said I would love to see Perl 6 get some traction. I just have no idea where it's going to do that. Maybe if a super high-profile project appears that's all done in Perl 6? Maybe if a small but influential cult of AI hackers falls in love with it? Maybe if it out-Pythons Python as the default entry-level "big data" language?

Because of the reasons listed here, for this old Perl hacker "write stuff in Perl 6" is stuck at the way-way back of the backlog, and well behind at least two other "write stuff in..." stories.

[0]: https://play.golang.org