I'm running my torrent preservation service, and many anime/jrock/jpop downloads start downloading only after weeks or months of waiting for a seeder.
Groups and individuals who used to be active on the scene has switched elsewhere and retracted their archives and XDCC bots.
There are Chinese torrent-to-web download services which seem to cache already downloaded stuff for a very long time if not indefinitely, sometimes you can download it from there if someone managed to use the service (they don't seed it over bittorrent though).