Earlier quoted context omitted.
I'm curious, why do you think it should have been killed off in favor of Atom? Do you mean in the sense of the terminology, or is there something inferior about RSS? Perhaps both should be killed off in favor of a JSON-based format.
Refer to my earlier comments: Atom is technically superior and more sound, and calling them all “RSS” is harmful by encouraging the inferior. JSON stuff? Eh, I feel that’s largely a solution looking for a problem. It’s too late to get universal support in clients (feeds aren’t popular enough and too much of the software basically on life support), so you’re always going to need to serve Atom or RSS as well, and once…
Where did this come from? You refer to an atom feed as RSS, someone decides to add RSS to their site, and they implement atom because that's how you do RSS. What's the problem?