Your observation that in WT publications this question was usually directed to young people rings true. Likely that's for two reasons, at least from the official JW perspective: 1. younger children don't wonder such issues until around puberty, so the WT publication writers were/are attempting to address what young born-in teens are thinking about ("Does God exist? If so/if not, what should I do?"). 2. the WT power structure is aware of the constant drainage of the youth, so they are attempting, however feebly, to stem the tide.
If I may play their advocate here (obviously NOT because I agree with them on multiple issues), wouldn't they say that an adult 's purpose in life is to recognize the principle at Rev. 4:11, that all creatures should recognize their created status and their creator, and respond to that by willingly, even eagerly, serving that creator, doing whatever the creator wants?
Please recognize that I am only playing their advocate in response to SBF's OP, not because I am defending the WTS. The WTS position here is one that has been long held by various Christian theologians, many of whom existed well before Charles Taze Russell lived.
Now, SBF, your version of the correct answer is no doubt awaited by far more of us than nicolaou and me. One request: please try to keep it moderately brief and to the point!
