>Perl 6 is a different language from Perl 5, and both are being developed actively. Perl 5 was at version 15, last I checked.

It wasn't always that way, however much certain luminaries try to retcon. Perl6 was originally intended to be, well, the next version of perl; it was only after the community's rejection that the decision to continue perl5 happened. It's not beyond the realms of possibility that the same thing could happen to python (though I certainly hope not, and stories like this suggest we're reaching the tipping point).