The Python foundation won't budge on the 2020 EOL date, for sure. RedHat will support it until RHEL 7 is EOL (~2027), but that's security/critical fixes only - while Python 3 gets all the new features and development efforts.

At some point, the opportunity cost of staying with Python 2.7 is higher than the one-time effort of porting everything to Python 3, so companies will move. Especially the likes of Google and Dropbox.

gevent vs. asyncio - sure, gevent is more mature. But asyncio is undoubtedly the better/nicer API. asyncio's explicit await syntax is much nicer than gevent's implicit monkey-patching, which makes it harder to reason about the code.

Tensorflow isn't really a new library, it was only recently open sourced.

As for Python 3-only libraries:

- https://pypi.python.org/pypi?:action=browse&show=all&c=595

- https://github.com/aio-libs

Also note that Django will drop Python 2 support in time with the Python 2 EOL: https://www.djangoproject.com/weblog/2015/jun/25/roadmap/

Also, many new Python-based open source projects are Python 3 only.