Of course there are plenty of examples of particular religious beliefs that have died a natural death. My favorite example is of the Shakers, known today for their fine furniture and for a peculiar belief that all sex was wrong. They lived in separate dorms to prevent any hank panky. Needless to say there aren't any real Shakers left today.
Contrast the Shakers with say Catholics or Mormans who promote creating as many offspring as they can. The Catholics are also very good at keeping their flocks in line. My philoshophy prof, who described himself as a recovering Catholic, once came up with any interesting bit of logic. It goes something like this, in order to be a good Catholic you must follow the teachings of the church and not stray anytime during your life. Since there is always a chance that you will stray during you life then it follows that the only real good Catholic is a dead Catholic.
I write this not just to poke fun at Catholics, even through nearly 2000 years of Catholicism has produced a plethory of comical excesses. I am interested in hearing others opinions concerning the durability of some religions over others.