Usenet files get taken down all the time. Rights holders send notices to the Usenet providers and they remove enough of the binaries where they can't be repaire

Usenet files get taken down all the time. Rights holders send notices to the Usenet providers and they remove enough of the binaries where they can't be repaired by the PAR files. Indexers are separate entities. Those are the ones who catalog and host the .nzb files. You see those go offline far more often but Usenet is still pretty small compared to torrents so they don't get reported as much.