Well google helped in a few ways, and fbook dealt the mortal blows imho.

Fbook got real open.. open APIs.. (as a busniess, publisher, etc), add your stuff, get into everyone's feed..

people starting using fbook as their rss reader.. you started seeing the like button everywhere and less of the rss button on sites.

google helped with this as word got out that they were penalizing sites for blogrolls and such.. a lot of people depended on third party rss parsers (presenters?) - and the juice was not worth the squeeze to have a convenient feed if it killed your google rank and all your traffic.

While google traffic was going down, facebook engagement was going up and things looked okay that way.

It wasn't until a while, (couple? / few(?)) years later that businesses started to realize fbook was manipulating the feeds.. a few started to say hey this isn't right!

But that message has not gotten to most of the users. Most still assume that they are getting the latest posts from the people / places they have 'liked' - and they do not know.

More and more businesses have started to notice the less and less traffic, and some have even been shaken down by fbook, offering to put them back into the chronological feed if they pay a price..

Users are now swamped with other things in their feed and they don't really notice.

I chuckled hearing Kim Kamando go off about this on her radio show a while back.. after hearing her tell so many people for a couple years about fbook this, and use fbook for that.. of course, many of her listeners never heard that show, as they had gotten use to getting updates for her shows through the fbk feed.

there's been a few other things over the years. The my.yahoo, pageflakes, startpages and similar never updated with modern graphics and thumbnails.. no one thought to give them a scroll feed or algorithms to push certain rss feeds to the forefront.. and the masses got use to the UI of the fbook non stop scroll..

I think to bring rss back we need more rss apps, ones with fbook like scroll, ones with sidescroll graphically like taptu had.. options for chronological only, add certain feeds to 'show first' - tap a feed info to explore more / similar..

I don't know which ones have these options as I only test ones that are ad free or premium.. and it's hard to suggest people use the ones I like.

but also a service that will send rss links to whichever app you want... (and keep an opml for you, with current and previous versions of your subscribed lists); i have not moved my reader and feeds to my new phone as it's a chore one by one.

like a send-this-rss button on a page.. you click it (tap it) - it sends a url to a portal like about.me - which then pops up a list of choices to send that link to your app, to your fbk, to your whatever -

Love to have a segway screen that gives options when you subscribe to rss to choose 'all entries' 'certain category(s)', etc

I use to have many rss feeds for certain categories or keywords parsed into different places.. then they changes, I could never find most of them like there use to - even using search engines to find the feed for various places' category like yahoo news, bloomb and such..

Something similar to what you see on some music videos links on youtube - when you click them you get a list of places to do what you want , amazon, spotify, applemusic, beatport, etc

If we add a new spec to pull with sent data, like ask for rss and send a few kb of data to get an enhanced feed *while giving some creds for stats, and ugh possible ad targeting, maybe data showing i'm-premium-subscriber give me all the patreon perks) - they will get more resources on the other end.. and graphapi handles this well today and was not a thing when rss 2 came out right?

/some thoughts.. not complete