Correct me if I'm wrong, but the idea of perl6 was announced in 2000, and perl6 was finally published in 2015. So there was a 15 year gap when perl5 was perceived on its way to become obsolete, but perl6 was not available.
I am unsure when the idea of python3 (first as python 3000) came to general knowledge, but it must have been some time between 2000 and 2004. Then python3 was published in 2008.
So the time between obsoleting the old version, before the new version was available, was notably shorter with python.
I thought there was a release in the interim that broke backwards compatibility and the went back to the drawing board. But it's that long ago I might be confusing it with Netscape.
There's also a good chance I'm confusing perl and parrot.