2014/1/8 Steven D'Aprano
About 70% of the top 200 projects on PyPI support Python 3, and downloads of Python 3 are very healthy, possibly even higher than downloads of Python 2.
I do not think that one is a particularly good metric. For each project hosted at PyPI how many are not there? People have personal projects, companies have internal software, and there are products that contain at least some python and are targeted at final customers, like games or Maya. Not everything is open source, but even if it is proprietary software it is good to have it since that way more jobs are offered and more people can earn money with this language, and that is a guarantee for its long-term success.
and minimise the risk of defection to other languages.
People threaten that, but it is an irrational threat. (Mind you, people do silly, irrational things every day.) If you think its hard to migrate from Python 2 to 3, when you get to keep 90% of your code base and most of the backward-incompatible changes are a few libraries that have been renamed and a handful of syntax changes, how hard will it be to throw away 100% of your code and start again with a completely different language?
I think human psychology works like that. Many people may delay the acquisition of a new car, but once they are committed to buy a new one they want the best they can afford (within their budget). Some languages may gain momentum and gain the "cool" vibe. We saw the rise of Ruby a while ago, and maybe a language that handles well multiple cores could be a strong temptation in the future. If people keep investing in python, small bits at a time, keeping their codebase always up to date, it is more difficult, IMHO, to commit to a full rewrite. Alejandro