It seems like just yesterday my NASA rocket scientist friend was asking me what this new-fangled RSS thing was. I explained, and his response was, "So they just reimplemented USENET?"
IOW, wat
In particular, my friend asked what people use RSS for. At the time, lots of people used it to stay current on news.
In short, calling RSS "reimplementation of Usenet" makes very little sense.
What you say is true, but my friend asked what it's used for. At the time, it was largely used too keep up with news.
Except for the mailing list, RSS is the only relatively-heavily-used thing on the internet that shares Usenet's "openness" virtue: namely, there is no single "gatekeeper" organization that a reader must rely on to follow the authors in his RSS feed -- the sudden trouble that the OP experienced when upgrading to Mountain Lion is about the most disruptive thing that could happen to a reader's relationship with the authors in her RSS feed.
(If the assertion I was responding to had been that the designers of RSS should have tried harder to emulate Usenet's subtler virtues, I would have agreed.)