No, it is a function of balancing the power handling capabilities of the components versus their weight which is a big deal in airplanes. If I fly a few circuits around the field the equipment stays cool. If do a full battery load of full speed aerobatics, she will come home warm to the touch. If I put equipment that could handle those currents without any noticeable warming, the weight of those components would change the center of gravity and she wouldn't do those aerobatics as elegantly. The wires warm along with the speed controller and motor. The wires aren't the issue. The whole circuit is the issue.