4.11. Can the Church be without a pope for decades?

Yes, if God permits it as a punishment for apostasy. Though it is an extraordinary situation, it does not contradict the Church’s indefectibility, because the Church’s doctrine, sacraments, and hierarchical structure remain intact in those who preserve the true faith.

The long vacancy is a sign of the Great Apostasy, not a defect in the Church, just as God preserved the true religion through a remnant in the Old Testament when most had fallen away.