If it contributes nothing to the discussion of actually making Perl a language useful to the problems developers face today, the site deserves the criticism.
That’s respectable and worthwhile regardless, but I don’t think performance was a major factor in Perl’s decline. If I start a project right now in Python instead of Perl, it will have absolutely nothing to do with Perl not being fast enough. That is to say, I doubt performance improvements of Perl 5 will help much in regaining ground.
It does - for example it talks about a project to make Perl faster.