I think it's a little unfair to point to Ruby as an example of a community getting it right. The motivation behind the 1.8-to-1.9 shift for a lot of people was the markedly better VM in 1.9 (which is roughly comparable to CPython, as it happens), and not necessarily the language features. Specifically the encoding situation in Ruby 1.9 is... interesting, and easy to find surprising edge cases in.
Also Ruby had a far smaller deployment and library base to convert. Get Rails and Sinatra ported and you're mostly there. There are as far as I know no significant commercial software that ships with ruby as its main scripting language. Ruby doesn't really have its equivalent of numpy and friends which has snaked its way into critical software in just about every field you care to mention. Ruby 1.8 -> 1.9 was more like Python 1.X-2.X
There is a difference between "right" and "much better" (the term I used). I was able to upgrade my code to use Ruby 1.9 trivially, and the result still worked fine on Ruby 1.8. The transition was downright painless for almost everyone involved. (Disclosure: I am the Jay Freeman mentioned in the thank you at the bottom of Yehuda's article on the Ruby 1.9 encoding changes and how they would and did affect Rails.)
