well, fads die and then repeat themselves sometimes. for instance, fancy brooches were worn a lot by my great-great grandmother, great grandmother, and grandmother, but my mother never wore them because she and all her friends thought that they were hideous. now, my sister, who is 20, wears antique brooches all the time. the older the better.
but the question isnt if fads can be revived. it is if something that many people do can die (paraphrasing with bad english—sorry gail).
philosophy is a thing that everyone does. every person has wondered “why am i here” or “what is the meaning of life” or some other question, which can include this question. so, is asking, “why are we here, on earth, living and breathing?” a tedious and banal question? yes. a remark saying “that’s what she said” can be less philosophical, but it is still something that many people state, just like “why are humans here on earth?”. i dont think that the latter is banal, and therefore, the former should not be banal either.