I have recently stepped out of my historical comfort zone and begun exploring areas outside of my usual purview. One of my recent interests has been early India. I am especially fascinated by the Maurya due to their impact, size, and sheer longevity.
It's my understanding that the empire's fall was largely due to a series of weak rulers after Ashoka, so let us presuppose that this is avoided or at least mitigated somewhat. How long can the empire last with its Ashokan borders? What factors would still threaten its survival?