>>29295952
depending on the exact timeframe you define as "past" it might be the fact that cctv cams are now even more widespread, even in shitholes. as well as internet access to post the material.
if you talk about a matter of a couple weeks/months then the reason might be because one or several resident posters grew tired of reposting the same shit over and over and their "place" got taken by some other people.
considering there's always a specific amount of people lurking the channels, some might notice there hasn't been a specific thread they liked around for a time and they start one themselves