When did Hollywood stop looking for heroes in history and only take them from comic books?
The purpose of Hollywood filmmaking is to make money, so they make films aimed at the broadest possible audience. Unfortunately, more typical filmgoers have heard of Spiderman and Batman than have heard of Jackie Robinson or Florence Nightingale; and real-life heroism seldom involves giant flying robots, sexy costumes, or any of the other staples of modern Hollywood cinema.