A Shortage of Perfect Trilogies

Hollywood has become infatuated with trilogies. Once a movie or a movie character shows a cult following, the studios almost always turn it into a franchise. The reason behind this is not far-fetched. They get to give fans more of the first movie and their characters and of course, they get to make more money from the budding franchise. There are those times when the decision to make a trilogy is not motivated by the above reasons but by the source material. That is, if a novel is adapted for the big screen, it follows that subsequent sequel novels will also be adapted except if the first movie failed to perform at the box office. That being said, it seems delivering the perfect trilogy has for the most part, eluded Hollywood.