It's complicated, and I think it's less malicious in a way that "kneecapped" implies. Sure, RSS still exists in some form, but I think the utility of it has been in decline, and a lot of 'content' simply isn't accessible by RSS feed anymore.
An argument can be made that they provided an RSS reader service no one could come close to matching and basically dominated the area. Google's deep support also helped it proliferate. It is maybe underrated that RSS was likely one defense the web had against the dominance of walled gardens and social media. It allowed a lot of sites to flourish that I think would not get any traction today.
The decline in support for RSS is more visible on the client side. Sure there are reader options for the determined, especially if technically minded, but that's a marginal population.
In today's hyperconcentrated digital landscape about the only thing that matters for mass market relevance are the default options on client software controlled by gatekeepers.
Mozilla too has abandoned RSS, which may or may not be correlated with them being (alas) increasingly irrelevant.
Eventually lack of popular RSS clients lead to slow decline on the server side as well. A new and fancy website today using a "modern" stack more likely than not does not support RSS, its fully aligned with the "follow us on XYZ" mentality.
I found a blog yesterday, from a well-known indie gamedev, with no feed at all. No RSS, no atom. It was quite shocking because the vast, vast majority have one.
I didn't say "decline in support for RSS" but there are many examples of them being removed.
Twitter dropped RSS completely. Facebook dropped them for pages. And then other large sites (Youtube I think is one if I recall right) made it less of a public feature.
Twitter is one that's pretty annoying because there is a lot that gets posted there first before it's published or not published elsewhere at all.
I mean that it kneecapped the idea of RSS in the social consciousness. Most people believe that when Google Reader shut down RSS stopped existing, if they even knew what RSS was in the first place.
A friend of mine — in tech — asked me the other day where I was hearing a bunch of stuff and I said “my RSS feeds” and he laughed at me. That”s what I mean.