Personally I think that biology may be a flawed approach for most applications. Although the others arr worthy ends in themselves just for its role in understanding ourselves in a forensic archaeologist try to replicate sort of way, let alone any potential insights to biological brains.

Biology is glacially slow in comparison and one of the advantages from computing is being fast.

I believe that not modeling it is partially by design as a result of responsibility and blame frameworks. If you depend upon possible actions taken by others to be safe you are reckless. Extrapolating from current motions is more reliable than trying to profile everything. "They are moving towards the street at 3mph and 20 ft away, their vector will intersect with car, brake to avoid collision or accelerate enough to leave intersection zone before they can even reach us" seems a more reliable approach. It isn't like a kid will suddenly teleport into the road.