Reddit sorta half did it with the “other discussions” or duplicate tab.
As an example,
https://old.reddit.com/r/news/duplicates/1lvi6kb/a_clicktocancel_rule_intended_to_make_cancelling/
I never saw any apps implement it, but it does look like it was part of the API, but maybe it wasn’t robust enough.
I also know at one point, and possibly still, is that it lacked URL normalization. So for example, exanple.com/headline and example.com/headline#topstory would be treated as two different articles.
Similarly https://youtube.com/watch?v=dQw4w9WgXcQ and https://youtu.be/dQw4w9WgXcQ
Would be treated as separate articles.
These are all fixable problems, but require work.
That’s exactly what piefed does actually.