This math is for future busses designed for city use - so batteries will be much smaller and therefore lighter, and the bus construction itself will be much lig

This math is for future busses designed for city use - so batteries will be much smaller and therefore lighter, and the bus construction itself will be much lighter because, as you point out, with a city bus pulling away ~5 million times in its lifespan, the cost of energy lost when stopping and pulling away far exceeds the cost of upgrading the frame to aluminium and other weight saving measures.