From the layoffs I've observed Recruiters were some of the top laid off roles.
Less recruiters means prioritization of efforts.
HN Who's hiring is probably a low priority platform. (Recruiter's boss doesn't know what it is, hard to instrument for tracking metrics)
If you really want to know how many jobs are out there it's better to index and crawl all the companies jobs page directly. Albeit much much harder to do than a single HN thread per month.