Reader was a synthesis of open web culture - it offered a hub of reading multiple streams of content in one formatted location, and it did so with the support of one of the largest companies on the earth with the ability to use its clout to affect change on other organizations and make that data available to them in the form they wanted. Google could have been the 800 pound gorilla of news publications a decade before Apple News even tried.
But they just, threw it away. That's what I want back - I don't care if it's RSS or some new fancy JSON-backed article exchange protocol - the transport layer and reader app itself is largely meaningless to me; the simple elegance of being able to read the news in one location without some designers notion of layout and overzealous marketers' idea of ad coverage, and having it be quick is much more powerful. No more 2-10MB garbage landfills to serve 20kb of textual information. No more fighting to make the content work on mobile - RSS was inherently responsive and accessibility-friendly.
The technological idea of federated content have largely died because Google decided it didn't want to support them, and nobody else - not Microsoft, not Apple, nobody - stepped up to take the mantle. It had a technological problem for Google - the fact that you could pick another reader meant that there was no instinctive centralization on Googles' service, unlike situations like AMP where they're literally the man in the middle.
And while Instant Articles and AMP are trying to fill that market gap, more often than not what I find replacing it is Twitter, which is comically filled with horrible misinformation and terrible sourcing practices that make it a haven of misinformation instead of... news. And that's a real damn shame.
Unless I'm missing something, they never did anything unique to "use its clout to affect change on other organizations and make that data available to them in the form they wanted"—it was just an RSS reader, and what you've described is exactly how I use my reader of choice (Feedbin). Many modern offerings even offer a feature to pull the full text for articles where it's not included by default.