Of course people should look at dates, but it’s clear many many don’t. I understand wanting the ability to reference what things sold for, makes sense. Maybe a flag put in the OP can mark as sold and it shows on the title of the thread as (sold).
I’m sure there are members here that could pitch in with the coding if they are open to it, it’s not a big request. I could help with cyber security but I’m not a programmer. Yes it’s a free site, but there’s nothing wrong with requesting feature updates, but people need to understand it’s a request not a right.