I hear you and yes, that is valuable. We have to optimize for the general case, though. It definitely isn't optimal to have threads like this one, and then another when the actual announcement is made, and then probably another thread when $thing is eventually released.

I’d love a tagging system a la steam game tags where announce-of-announcement was a tag with a community of interested and engaged people who were vetting and tagging and hashing out what it means to be an announcement of an announcement. And then also there could be another community of similarly minded announcement-of-event people, likely with a bit of Venn diagram overlap, operating independently. And so on and so forth.

It's not going to happen. Not "fragmenting" the community, but rather keeping everyone in the same "silo" of topics, is kind of core to the identity of the site. If you want tags, that's a thing Lobste.rs is good at.

Or just ignore posts that don't interest you, it's way easier

Like the lobste.rs tagging system? I'm not sure how popular that would be here, but it might be cool.

There are lots of places to learn about a major Apple event (if anything, it's hard to miss it) that aren't the 30 slots on the HN front page. Yours is a variant of the 'everything is related to everything somehow' rationale with which you can argue anything is on-topic on any form that has topic rules. It's a fun argument but makes for lousy forums.