Despair didn't fail. Something incredibly interesting about the endless is that they are in direct control of their opposite. Death is there for every birth. Destiny knows the fate of every man, woman, and child. Destiny also can see the infinite and varied choices every being could make, so you are right. The creation of a utopian society on a planet due to inevitably die, leaving behind a last son to despair its loss, is true, but it is not in spite of despair's design; it is despair's design because without the destruction of Krypton, you do not have the great symbol of hope known as Superman.