I wonder if it would have been able to survive the next two thousand years of invasions. Looking at a map of the region, one would think that the Hindu Kush would be an impassable barrier, but steppe empires like the Yuezhi, Kushan, White Huns, and Timurids were able to conquer Gandhara and Punjab so many times.
Was there any particular mountain passes that were commonly used to cross from Central Asia into India? The Kushan Pass?