Difficult second generation

Rodney Stark writes;

Having surveyed a large number of [new religious movements] ... I noticed that it was typical for the founding generation to apparently lose hope of saving the world, and to turn their movements inward, as they neared the end of their lives. That is, unless something comes along to renew hope and commitment, as the first generation evaluate the results of thirty or forty years of conversion efforts and see that they have succeeded in attracting only two or three thousand members (if that many), they are inclined to lose heart. As this takes place, often a new rhetoric is voiced; this de-emphasizes the importance of growth and explains that the movement has succeeded in gathering a saving remnant, which is all that was ever intended, actually.
Rise of Christianity, p. 185