This article makes no sense. ES6 allows you to express things more succinctly, but it's not a React killer. You'd still be missing a declarative UI renderer if you were starting out framework-free, armed only with ES6.
And it's not a killer of other frameworks, either. ES6 doesn't give me the wings I need to ditch Winston for logging or Redux for managing state. Not sure how this article got to the front page, but it certainly shouldn't stay here :P