Silicon Valley hype.

imagine a library organized chronologically, or even the morning edition of a newspaper.

Feeds are like newspapers, but the library analogy is nonsense.

Of course feeds with user input need to be weighted. That seems obvious. Consider Hubski. We have a global feed mostly ordered by time, but weighted by shares. Like almost every similar community. That seems obvious to me; and we still call it a feed.

I can't speak for Reddit or Facebook, but Hubski's feed isn't dying anytime soon.