> Meanwhile, automotive companies aren't scared of moving parts. A car has loads of spinning parts already; they have mastered the art of making spinning things that can keep spinning for thousands of hours.

Almost an understatement.

A typical car wheel hub with a 20-27 inch tire diameter has experienced around 75-100M full rotations by the time it reaches 100K miles.

Meanwhile, the engine probably has revolved ~5-10 times more during the same time.

I may be wrong, but I think the concern was delicate components protruding from the body are susceptible to damage in urban areas.