I think it's just a matter of personal casting style, taste, situation, etc. It's not always about cost. Some guys like bamboo, My dad fishes almost exclusively fiberglass rods. Me, I like slower action graphite and have learned how to make them do what I need them to do. For a lot of people, the stiffer and/or faster rods are the answer. Some of my rods are inexpensive, some are pretty spendy, it's about having the tool for the job that lets you enjoy the experience. The reason there are so many kinds of rods out there is that there are so many different fisherman with so many different preferences, each as valid as the last as long as the fly gets in the fishes mouth. For me, the diversity is a lot of the fun.