Various mechanisms are in place on different wikis to address link rot, e.g. parameters like "archiveurl=" and "archivedate= " in templates like cite_web and cite_news on enwp that allow to link to archived versions of the cited URL, or https://ru.wikipedia.org/wiki/%D0%A3%D1%87%D0%B0%D1%81%D1%82%D0%BD%D0%B8%D0%BA:WebCite_Archiver , which creates and adds archival links automatically.
It would be good if Citoid would provide similar functionality, so as to address link rot, and in a way that is more consistent across wikis.