It's an interesting question. I'm sure there are many theories but the one that is probably most valid is the old "it's always been done that way so it would look funny otherwise."
There are many things about motorcycles that ignore technological progress or practicality in the name of tradition. Harley-Davidson has made it a sucessful corporate strategy.
There are many things about motorcycles that ignore technological progress or practicality in the name of tradition. Harley-Davidson has made it a sucessful corporate strategy.