Grandstone wrote:life wouldn't even be worth living if everything and everyone for hundreds of miles was gone.
I disagree.
Certainly some people, when faced with the prospect you just described, wouldn't find life to be worth living, and such a life would almost certainly be a drastic change from the life that any of us are used to enjoying. However, such a life wouldn't be uncommon for other people, and history has shown that groups routinely seek such conditions. For example, the Bedouins of Arabia or the nomadic tribes of the Asian steppe wouldn't find such a situation to be either disastrous or uncommon. The mountain men of American history frequently sought out solitude from civilization, and various pioneer groups sought new home far removed from others.
Now in the context that you are describing, that of a post nuclear world, life would most assuredly be very different from what it is now, and some people would rather give up and die then face the hardships that it would bring. However, to say that it wouldn't be worth living is to say that one's happiness and purpose are derived from those around us, the people and things that make up our daily life. If such is the case than any number of events would thus make life "not worth living", be it a car wreck, loss of employment, burglary, etc. If, however, one finds their happiness from someplace else, someplace that can't be stolen from you by force or deceit, then regardless of what happens life will always be worth living.