I submitted this with the correct 8.1 link, and somehow HN keeps changing it to the 8.0 link automatically upon submission! Super weird behavior on HN's side.

I tried re-submitting the 8.1 link, and it did it again, and also marked it as a dupe. Maybe I'll try submitting the corresponding blog post instead, although the title on that doesn't explicitly mention how 8.1 is released, so it's unlikely to get traction here...

Regarding your second paragraph though, you're completely mistaken. MySQL 8.0 used a rolling release model of adding new features in every quarterly release. They're just changing the versioning scheme starting today with 8.1.