Answer:
   
   The orginal Hebrew word (hevel) which you translate as "futile" is
   better translated to mean "absurd". Hevel is also the word for
   "vapour" or "mist", so King Solomon's point is that things of this
   temporal world are as short-lived and thin as vapour, and hence
   absurd. He means to contrast them to spiritual things that are
   immortal and holy, as well as more substantial and real. Interestingly
   enough, we take spiritual things to be vapourous and insubstantial,
   and worldly things to be substantial and more real. But King Solomon's
   point is that the opposite is true. As such, the word does nothing to
   suggest "futility" whatsoever; instead, it speaks to a true and bold
   hope based on faith in things spiritual-- most especially G-d
   Almighty.