The "most recent big discussion" is still 11 years ago. As your list shows, all the more recent submissions got much less attention - most don't have even 1 com

The "most recent big discussion" is still 11 years ago. As your list shows, all the more recent submissions got much less attention - most don't have even 1 comment. HN permits some duplicates, particularly over a long enough time. Even recent duplicates are allowed, if previous submissions did not generate discussion but the moderators feel that the content is interesting enough and that it didn't get a "fair shake".