Their plan is more nuanced than "at the end of 2019". From a numpy feature standpoint, it's EOY 2018, bugs through EOY 2019:
> Until December 31, 2018, all NumPy releases will fully support both Python2 and Python3.
Starting on January 1, 2019, any new feature releases will support only Python3.
The last Python2 supporting release will be designated as a long term support (LTS) release, meaning that we will continue to merge bug fixes and make bug fix releases for a longer period than usual. Specifically, it will be supported by the community until December 31, 2019.
I guess it's due -- Python 3 finally has some improvements to the runtime that I think will start to pull more Python2 people over.