Says who?? Someone with delusions of grandeur, obviously. Because that's not up to anyone to say. Python 2 is obviously NOT going away any time soon. You can't just look at reality and claim the opposite just because it pleases you. Python 2 is here to stay and is in MUCH better shape than Python 3, in terms of actual production usage globally. Python 3 is a bad joke that someone wants to force down people's throats…
Of course you can continue using Python 2.x after 2020 but you will receive no security/bug fixes.