Survival: Those who walked upon the Earth still, didn’t know of or hope for anything else. When it’s not just your world, but the whole world, that comes crashing down, immediate priorities tend to stay simple. Those who survived the impact and the subsequent ‘winter’ became single-minded scavengers, wanting only what they could consume.
It was in this state that the crew found every survivor: concerned only with lasting another day. They did not respond to the plans for rebuilding, did not comprehend the need to secure life on a timescale longer than a season, longer than food would last.