There’s a lot that goes into the success of social media over the last couple decades and figuring out the best ad revenue models was a big part of it.
That in turn led to other companies with the ability to set things at the time gradually deprecating and removing their build-in feed readers (thanks Mozilla, thanks Apple) and the result is that RSS "failed".
It didn't fail, it was murdered so Google could promote their failed social media network.
However, RSS was never very popular outside some small tech circles, and Mozilla and Apple saw that the same way that Google did.
Mozilla is nothing more than controlled opposition that Google can prop up and say "See, we're not a totally monopoly" while Apple at the time could see nothing beyond the piles of money that the iPhone was making them, to the point where even their desktop/laptop lines suffered.
Instead of that, they removed the comments and replaced them with something worse that no one ended up using.
The former would be a more impersonal source of information and discussion, whereas the latter would have been where you put your personal connections.
Unfortunately Google wanted to do both in the same product, and thought that Circles would be sufficient to create the distinction, but the kind of stuff someone might want to expose to an impersonal connection is drastically different from the kind of stuff they want to expose to personal connections, to the point that they should arguably have completely different UIs.
Nevertheless it seems to me like the network effect was the main thing, and Reader could've been a huge step there.
To make money from Ads. So parent is right, RSS was killed because of the Internet Ads.
I still have these exports, backed up to a CD somewhere.
Edit: actually I would say its more like an infinite closet but the more clothes you had the longer it takes to find something to wear the next day until things becoming unbearable and you just close the door to your closet, lock it and then rent clothing for the rest of your life.
It, of course, limits the medium to, well, social media proper, peers talking among themselves for the enjoyment, not making it a full-time job. It pushes for-profit stars elsewhere.
It of course does not solve the problem of hidden ads ("shilling"), product placement, etc, in more popular feeds.
There is certainly room for strictly non-commercial communication, where the value is in the human connection (talking to friends) or fame (being a local luminary). But certainly it's not going to be a medium fitting for everyone, and for al types of content.
I'm finding increasingly harder to follow some podcasts as well.
More and more are centering their distribution through Spotify. Reason: money. Either to fund the minimum needed or to give them some margin that Patreon or similar methods are not able to.
It's not a technology issue, in today's world, most content that would be on an RSS feed comes with ads built in.
There's really only two driving forces in online creative activities:
1) money
2) clout
RSS is a terrible medium for both.