As far as I can tell (including looking at third party analytics attempts), there had been a massive increase in users over the last 3 years. Smaller communities tend to hold their trademark character a lot better. Pure speculation, but (beyond the bots) I suspect that a lot of the newer users are younger, and the attempt to be a bit more focused and sincere here is something they miss before they start posting.

It is now easier to mass create and program dormant accounts. They can be used later for any purpose.

I wouldn't be surprised to see a "Show HN: I made 1000 accounts with more than 20,000 karma with Claude Opus 6.7" in the future

You only just noticed this now? At the very least, HN is subject to the same intellectual capture that's taken over (seemingly) the whole damn world the past decade.