RSS is a feed that users control the content, arrangement, and monetization of (the creator can still monetize the content but not the feed itself).
It is "dead" because Facebook, Instagram, Google etc... can make more money if they control the content. In theory these services could add value through curation and presentation but they tend to suck donkey balls in this regard. RSS has been minimized so that the walled gardens can be shittier without losing revenue.
So yea, RSS is a fucking amazing piece of technology that is a no-brainer if you know it exists.
my experience with rss is that its a data format. if its widely supported by publishers then its automatic win.
i guess it allows for tbe diff'ed content updates to be modularized away from reloading the entire page over and over again. deffinitly reduces waste and improves subscriber retention/loyalty.
there is nothing in the standards that includes deduplication (AFAIK). but client devs always include it.
Back in the day I was a big Google Reader fan, then they went and killed it off. Now I use a combination of Feedbin on the web and the Reeder app on iOS.