There's been no such penetration at all. Because current Perl 6 implementations cannot run Perl 5 code, everyone sticks to some version of Perl 5 for "perl" an

There's been no such penetration at all. Because current Perl 6 implementations cannot run Perl 5 code, everyone sticks to some version of Perl 5 for "perl" and uses "perl6" when that is wanted. (That said, there are at least two current projects working on getting Perl 5 support up and running in Perl 6.)