Just for amusement value: Consider what it would take for a space presence to survive independently any threat likely to clean out all 7 billion people on earth. - There are no suitable biosphere's anywhere in reach, so such an outpost would need to build and maintain one with no external resupplies. It also needs to be distant enough, and isolated enough from earth that contagions and conflicts are unlikely to involve them. So, it needs to be a complete industrial society, and it is obligated to be a hermit kingdom/republic. The complete industrial society is kind of a killer problem, because supporting that needs quite a substantial population, so it requires something on the order of moving dozens of millions of people to the moon system of Uranus. So, yhea, not seeing the point