This is the key - you
need to cannibalize from the "new" for the "old" if you're making a grandiose change with no set release date. Perl 5 continuing to get some "back ported" improvements from Perl 6 would have kept it alive for quite a lot longer.
You run the risk of killing the new in the cradle, though, and often that scares people.
from __future__ import coolshit
that's the way you wanna roll