With Elpis locked away, in other words, we are, like Epimetheus, capable of living from day to day, blithely ignorant of, or at least ignoring, the shadow of pain, death, and ultimate failure that looms over us all. Such an interpretation of the myth is, in a dark manner, optimistic.
This makes much more sense to me, as I see hope rather than doom as more innate trait to humanity. Ironically, the fact that I hold this belief proves my point.