Apparently they're just a bit tougher or different to search through now. Sorry, meant to add a correction before I fell down the "reread old RP threads" rabbit hole.
Nothing has changed in the last few years. I am currently rebuilding the site's search index and it will finish in a tiny bit, so maybe that will help.
It's been a while since I last did this, but you have to search the archives specifically if I'm not mistaken. Basically archived results will not appear through the search thread unless you are specifically filtering for archived results.