this isn't exactly breaking news.
I don't recall seeing it mentioned here at MacRumors that it'd officially been killed, though I recall people asking if it had been.
you're right in that there was no official MR news story about the iPod Hi-Fi's end, but it was covered in a story following the announcements yesterday.
even though it was not covered in a news story, it still is not surprising that it was discontinued, given that we've heard nothing about it from Apple since its release over 18 months ago.
The story you linked to actually questions if it was discontinued or not, and only says its no longer in the Apple store. My linked article claims they've received official word from Apple.