The sarod, or indeed any musical instrument, is a perfect example of co-evolutionary technology.
I was just thinking of the length of the strings. In Bhairav the distance from Risabh to Gandhar (D flat - E) on the fingerboard is a stretch. My hands must be of average size - if not slightly larger than the average in the Middle East and Asia over the last few hundred years. I don't think anyone arbitrarily decided out of the blue that this was a good size for the instrument. If that had been the case then the first one would probably have been abandoned as too difficult to play. The concomitant innovations needed to be developed in tandem at the bodily, cellular level. The fingers needed to be trained to work with this machine. And of course the actual music also evolves and accommodates simultaneously, becoming the exploration of what is realizable.
So the biological, the technical and the metaphysical all push and pull one another along a path of development that can only be seen in hindsight. Relatively small, iterative adjustments in each eventually lead to a complex, interdependent system. This is evolution. A cycle of innovation, discovery, construction and obsolescence. It is also music.