Yes. People will come out with excuses like TECHNOLOGICAL PINNACLES or what ever, but the main reason will be that Lucas will have told them to do it this way, and it doesnt make much sense, they just wanted people to be able to relate to the movies. i.e baddies shoot green and fly TIE fighters, goodies shoot red, star destroyers, gold droids, R2 units etc. Edit : Beaten to it. Things dont stay in fashion for 3000 years.