In my opinion, those are results of Perl losing mindshare. Numpy is not exactly hard (R has a significant fraction built in, and there's an old standard library for Scheme, of all things, that is very similar). Perl was perhaps the leading language for websites, but the Perl 5/6 situation just confused everybody as it dragged on, which made Python and Ruby libraries seem more attractive.
> And I guess Perl also never had its Django (or Rails).
It’s got two of them - Catalyst (older still works fine) and Mojo - newer and shinier.
I think python is a better fit for mathematical work. I like to say that python helps you think more like the computer does, and that perl helps the computer think more like you.
rails as far as I understand is opinionated and optimised for CRUD / database type applications. Catalyst is much more agnostic about the model you use. It provides the flexibility and a way of structuring the code and providing debug tooling that makes structuring a decent size app well reasonably easy to do.
And I guess Perl also never had its Django (or Rails).