Answer

If by “extinct” you mean that public, wandering Digambar munis were no longer visible in North India for centuries, then the tradition was revived in the early 20th century, especially through Ācārya Śāntisāgar. The revival did not mean the tradition had completely vanished everywhere; scholars note that the word “revival” does not imply total disappearance, because some ascetic and teacher-disciple continuity still existed, along with bhattāraka seats and lay support. ( tile.loc.gov)

Explanation

The process was basically this:

• First, the tradition was preserved in a limited form. In North India, bhattārakas and temple-based learned specialists helped preserve ritual life, texts, and religious discipline when full naked muni wandering was no longer common. ( tile.loc.gov)
• Then Śāntisāgar took step-by-step renunciation. He received kṣullaka dīkṣā in 1915, ailaka dīkṣā in 1918, and then full muni dīkṣā around 1919–1920. After that he wandered, lived very strictly, and became the most visible living example of the Digambar muni ideal. ( pure.manchester.ac.uk)
• His discipleship created a new living lineage. In 1924, Śāntisāgar initiated his first disciple into full monkhood, and after that a proper saṅgha began to form around him. From his time onward, the ācārya title and the living succession of teachers were revived in a practical way. ( pure.manchester.ac.uk)

So, in simple words: the Digambar muni sampradāy was revived because one powerful ascetic, Śāntisāgar, re-established the living teacher-disciple chain, inspired lay support, and initiated new monks so the order could continue again. ( pure.manchester.ac.uk)

Spiritual Understanding

In Jain Dharma, a sampradāy is not kept alive only by memory; it is kept alive by practice, discipline, and transmission. The Digambar muni tradition revived because someone again lived the ideal with full seriousness, and others were inspired to follow that path. This shows how true renunciation can reawaken a dharma lineage when the right conditions and sincere guidance appear. ( pure.manchester.ac.uk)

Takeaway

The Digambar muni tradition did not restart by scholarship alone. It revived through actual ascetic living, initiation, and public example, with Śāntisāgar at the center of that renewal. ( pure.manchester.ac.uk)