In Jain tradition, the Purvas did not disappear suddenly; their loss was gradual and has a few key reasons that both Digambar and Shvetambar accounts broadly agree on:

1. They were only memorized, not written

- In the early centuries after Bhagwan Mahavir, all Agams, including the Purvas, were preserved only by oral memorization. - Such huge, deep texts (14 Purvas) could be remembered fully only by a few very highly capable ascetics called Shrutkevali. - When even a small link in this oral chain weakens (one teacher does not teach fully, or disciples cannot memorize fully), that portion is slowly lost.

1. The 12-year famine and scattering of monks

- Around 2nd–3rd century BCE, a long famine in Magadh is described in Jain tradition. - Many monks, led by Acharya Bhadrabahu, moved towards the south; others stayed in the north. - Because the Sangh got divided and was struggling just to survive, systematic teaching and memorizing of the vast Purvas declined sharply. - This famine period is remembered as a major turning point in the loss of original scriptures.

1. Very few knew all 14 Purvas – and they set limits

- Tradition says Bhadrabahu Swami was the last to know all 14 Purvas completely (the last Shrutkevali). - His disciple Sthulabhadra is said to have learned only 10 of the 14 Purvas; Bhadrabahu, seeing the danger of misuse (occult powers etc.), forbade passing on the last 4 Purvas further. - Because of this, even within the tradition, some parts were intentionally not transmitted, so after a few generations, complete knowledge naturally vanished.

1. Weakening memory and spiritual discipline over time

- As we move further from Mahavir’s time, Jain texts themselves say monks’ memory, austerity, and discipline gradually decline in this era (avasarpini). - Fewer monks were capable of holding such enormous scriptural detail in memory. - With each generation, small gaps in memorization and understanding grew, until the entire Drstivada (12th Anga), which contained the Purvas, disappeared.

1. Difference in Digambar and Shvetambar standpoints (but same conclusion: Purvas are lost)

- Shvetambar view (simple form): - At the Pataliputra council, monks tried to collect and recite the Agams. - They could preserve 11 Angas, but Drstivada (with Purvas) was already incomplete / lost, because the only full knower (Bhadrabahu) was absent or had not taught it fully. - Digambar view (simple form): - Because of famine and decline, all original Agams and Purvas were ultimately lost. - What survives today (both in Digambar and Shvetambar canons) is later re‑composition and summary, not the original Purva-texts themselves.

So, why did the Purvas fail to be preserved?

• Because they were huge, oral-only texts,
• Depended on very few extraordinary memorisers,
• Were hit by historical crises like famine and migration,
• And, according to tradition, were partly withheld from further transmission to prevent misuse and because of moral decline.

As a result, both Digambar and Shvetambar traditions agree today that the original 14 Purvas and the Anga Drstivada are no longer extant, and only traces of their teachings survive in later Jain scriptures and commentaries.

You can read a concise overview of the 14 Purvas and their loss here